Precision In A Won Position

Okay so this occurred in a blitz game, but the game was rather accurate.  

After a long struggle, white managed to punish black for choosing an unorthodox line against the English opening by picking up a pawn.  Unfortunately, like any self respecting master, black refused to just go away, and found a way to create counterplay.

This puzzle emphasises the importance of precision in 'better' positions.  

Black has just played Ke6-d5.  What is black threatening?  Is this just a draw or can white play for a win?