Sushi Azabu
A Michelin-starred subterranean hideaway in Tribeca, Sushi Azabu is an authentic and "sublimely" small den that serves up fresh-from-Japan fish and Japanese cocktails and sake. With only nine seats in the place, you'll definitely have to make a reservation beforehand. And don't get the lower level confused with the ground floor izakaya, which boasts a much more casual setting (without the Michelin star).
Sushi Azabu, 428 Greenwich St.
[Photo via @yyan0222]