How to beat ‘Vienna Game: Falkbeer, Mieses Variation’ as black?

After 1.e4 e5 2.Nc3 Nf6 3.g3, it seems white has a clear plan. After h3,Nge2,0-0, white is ready to play f4 and attack at kingside.

As black, what should I do? Should I open the center? Or I should push the pawn at queenside? What is the best plan for black?

I have check the database. It seems 3. ..d5 is strong. After 4.ed Nxd5 5.Bg2 Nxc3 6.bc, black get a good position. Now black can play Nc6 or Bc5, to develop and control the center. I think this position is easy enough for black to play.

Open it up. Isnt that the point of Nf6?

I think Nxd5 is enough, but c6 is also interesting. If 5.dc Nxc6,white is too slow and black has enough compensation for the pawn. Maybe white should play d4 and try to be positive. 

Today I play a game, it's a Spanish game. After 4. Ba4, black plays g6. Though I didn't learn this move, I find the idea to beat this move is just like 3. ..d5 in Vienna. This is very interesting. 

Funny enough I struggle as white the most during this variation

taking must be fine for white, but for the not so brave 5. d3 actually looks fine. You see a similar idea when declining the Smith-Morra gambit. 

d5 lines i think are psychologically dangerous because they take white off his comfort zone with the near universal, nge2 0-0 h3 kh2 f4 response. White also needs play a bit actively since he often allows his pawns to be doubled on the c-file

I like play 3.d5 and 4.c6 with some 5.Bg4 ideas.