Sicilian Defense

I understand that as a beginner you should focus more on the opening theory and not openings, so I am not asking for lines to memorize or anything. What I am asking is what is the ideas to be thinking about if you open e4 and black responds c5 what should I be thinking about doing and/or developing. 

https://simplifychess.com/sicilian-defense/index.html

https://www.youtube.com/results?search_query=hanging+pawns+sicilian+defense

As for books on the Sicilian there are two approaches 1) books specific to the Sicilian itself or 2) general openings manuals, providing broad overviews of many openings

I have recommended books of both categories here...

Good Chess Openings Books For Beginners and Beyond.....(search 'sicilian')...

https://www.chess.com/blog/RussBell/good-chess-openings-books-for-beginners-and-beyond

In particular, for the specific openings category 1, for those looking for initial exposure to the Sicilian, I suggest to consider John Emms' "Starting Out: The Sicilian", which provides an excellent overview of all the variations of Sicilian Defense.

For an openings manual containing overview coverage of many openings, perhaps the best single volume book of this type is Paul van der Sterren's "FCO: Fundamental Chess Openings".  It does an excellent job explaining the fundamental themes and plans of all the openings, including the Sicilian.

https://www.chess.com/blog/RussBell

This is all you need for now:

Opening Principles:

1. Control the center squares – d4-e4-d5-e5
2. Develop your minor pieces toward the center – piece activity is the key
3. Castle
4. Connect your rooks

Tactics...tactics...tactics...

The objective of development is about improving the value of your pieces by increasing the importance of their roles. Well-developed pieces have more fire-power than undeveloped pieces and they do more in helping you gain control.

Now we will look at 5 practical things you can do to help you achieve your development objective.

They are:

1. Give priority to your least active pieces.

• Which piece needs to be developed (which piece is the least active)
• Where should it go (where can its role be maximized)

2. Exchange your least active pieces for your opponent’s active pieces.
3. Restrict the development of your opponent’s pieces.
4. Neutralize your opponent’s best piece.
5. Secure strong squares for your pieces.

Don’t help your opponent develop.

There are 2 common mistakes whereby you will simply be helping your opponent to develop:

1. Making a weak threat that can easily be blocked
2. Making an exchange that helps your opponent to develop a piece

Pre Move Checklist:

1. Make sure all your pieces are safe.
2. Look for forcing moves: Checks, captures, threats. You want to look at ALL forcing moves (even the bad ones) as this will force you look at, and see the entire board.
3. If there are no forcing moves, you then want to remove any of your opponent’s pieces from your side of the board.
4. If your opponent doesn’t have any of his pieces on your side of the board, then you want to improve the position of your least active piece.
5. After each move by your opponent, ask yourself: "What is my opponent trying to do?"

I wrote a blog post about this some time ago:
https://www.chess.com/blog/harriw/what-if-black-does-not-play-e5-the-sicilian-case

There are more perfectly good lines than what I've given, those can be found in books/databases. The blog post was just meant to be some first aid type of help to someone who does not know the Sicilian at all.

1 e4 c5
Opening principles:
1) Play only your d- and e-pawns
2) Do not play the same piece twice
3) Knights before bishops
4) Do not pin the KN with the QB before opponent has castled O-O

Application of the principles:

2 d4 2 d3 2 Nc3 2 Nf3
Say 2 Nf3. Now black has several possibilities:
2...d6, 2...e6, 2...Nc6, 2...a6, 2...b6, 2...Nf6, 2...g6
Say 2...d6
Now again 3 d4, 3 Nc3
Say 3 d4
Now 3...cxd4
Now 4 Nxd4 or 4 Qxd4
Say 4 Nxd4
Now 4...Nf6 or 4...Nc6 or 4...e6
Say 4...Nf6
Now 5 Nc3
Now 5...a6 or 5...g6 or 5...e6
Say 5...a6
Now 6 Be2 or 6 Bc4 or 6 Bd3 or 6 Be3
Say 6 Be2
Now 6...e5 or 6...e6
Say 6...e5
Now 7 Nb3
Etc.

I’ve practically broken all of the listed opening principles lol that’s hilarious.

I like the Sicilian because of the imbalance, positions, tactical opportunities and counter play/attack. If that suits your personality or desire, why not try it out?

Well, after 1. c5 white has a couple of options that differentiate from the main options which is to play 2. nf3, they could play the Closed Sicilian, the Smith-Morra gambit, etc which are all pretty different from the Open Sicilian

After 2. nf3, the four main options for black are to play 2. d6, 2. nc6, 2. g6 or 2. e6

I don't know much about the 2. e6 variations

2. g6 is very similar to other Dragon Sicilian setups where black is basically inviting an attack and trying to produce counterplay with the Fianchetto and the Queenside pawns

If 2. nc6, if you opt to play the Open Sicilian with 3. d4, you'll have to expect a Kalashnikov or a Sveshnikov with e5, in which what often happens in the main lines is that black gets aggressive play and piece activity in exchange for a bad pawn structure and a weak d6 pawn

2. d6, the modern main line, imo is the most "Sicilian" in character as opposed to other options. In the main line English and Yugoslav attacks of the Najdorf and Dragon, both sides are basically going out for an all out attack with moves like a6 + b5 for black and f3 + g4 + h4 for white, where both sides try to create open lines with pawn storms

I find the most effective response for White against the Sicilian is the Alapin variation, meaning your second move as white is c3, with an eye toward later moving d4 and controlling the center.   The downside of c3 is it takes away your knight's most natural development square, but there are always tradeoffs.

The Alapiin is simple to learn and it often throws Sicilian players out of their comfort zone because the resulting position looks nothing like any of the more common and vastly studied Sicilian variations.

Here's a short, but very good video on it:  https://www.youtube.com/watch?v=VxV8l3x7hOg

I hope it helps you!