Assulin, who was available on a free transfer after leaving Barcelona in July, had been chased by several clubs but City moved first to snap him up on a two-and-a-half-year deal.
He said: "I had heard a lot about City, and as soon as I saw the club I wanted to stay.
"I'm at a great club and I hope to be here a long time. I have to take my opportunity and learn every day in training."
Assulin, who became the youngest player to be capped by Israel two weeks before his 17th birthday, revealed former Barca player Yaya Toure had played a part in his decision to move to Eastlands.
"I speak with Yaya every day - and I hope to be playing alongside him. I hope to show I can play at this level."