Make a move. At this point he knows you're interested. If he's into you he'll either repeatedly CONNECT with your glances, smile back or both. Time to make a move and seal the deal. This is often the hardest part for most guys.
Seal the deal. He'll eventually tire of playing peek-a-boo, so don't miss your window to say hello.
There are two ways you can seal the deal:
(a) Use the "heat seeking" technique where you walk right up to him, introduce yourself and keep the conversation going, or
(b) try the "hit and run" move, where you write your number down on a piece of paper, give it to him, tell him to go out with you, then walk away. I was eating dinner with friends once when a guy came up to the table, set a piece of paper in front of me and said, "You. Me. Dinner this weekend." I sat there stunned and he just walked away. Did I call? You bet, if only for the intrigue.