It may pay you to hook up with the NYC Kiters group on Yahoo groups for advice about where to go in/around NYC. There's flat water kiting on Great South Bay - contact NY Kite Center -
www.nykitecenter.com/ or try friending them on FB -
www.facebook.com/kiteboardingisfun - they do day trips out to the island (apparently) but are a bit strong on the $$$.
Other options are kiting in/around Gilgo beach but (like everywhere), there are some local rules etc that are strictly enforced, apparently by local Park ranger types as well as local crew.
Can't comment on Chicago unfortunately, but there are very good winds in & around San Fran. There's a big kite racing community over there. Apparently.
If you're into waves & have a car or transportation, you might want to try Waddell Creek, about 75kms south of San Fran, just north of Santa Cruz.
The best bit of advice I can give you is to take a steamer. If you're kiting on the west coast, northern Cali, you'll need a very very warm/thick steamer. Recent experience taught me this. I'd also strongly suggest booties, and if you want to go the whole hog (esp for Northern Cali) a hood. Crew might laugh that this is an over-reaction, but the water over there is cold. Colder than any thing we get in WA.
PM me if you want more info.