Chow Hound Dog, Wok Hai is a tricky thing. It is hard to find it consistently in any place because there are several factors required to achieve it: good technique, high heat, and immediate consumption of prepared dish.
I would guess that all the places in Chinatown have the high heat requirement. The skilled cooking technique is tougher to find as not all cooks are created equal. But the toughest thing is finding a place where the food will be consistently brought to you as soon as it comes off the heat. Key here is consistency.
Your best chance of finding wok hai: Find a reasonably authentic Chinese resto where you like the food., and where there is not a lot of English or French spoken. Order dishes that really accentuate this quality, in particular, stir-fried dishes. Go at a quiet time, earlier in the evening, before it gets too busy, and in a smaller place where there are less orders to pump out. Order a few dishes at a time. Hope your waiter is prompt, and hope for the best.
Wok Hai is an ephemeral, elusive quality. I have experienced it at various places in Chinatown and around town, but not consistently (except in the hands of Ming, who always worked in small places, and who would bring the food out to us himself as soon as it came off the heat). I have occasionally encountered it at Kam Fung (on quieter nights, or sometimes we get lucky, the stars align and a dish comes out fairly quickly), once at VIP, more consistently at Fu Kam Wah, at Cuisine Szechuan and fairly often at Cuisine Bangkok (in the Fauberg), to name a few places. But the potential is there at any good Chinese restaurant. I have not personally been, but good reports have been posted about Amigo 168 in Chinatown. Please note: Fu Kam Wah, Cuisine szechuan and Bangkok are not in Chinatown. And Bangkok is actually Thai.
Hope this helps a bit! I'm hoping others will be able to help out a bit.