Zocalo is on East 82nd Street, and you might easily miss it if you were just walking on 3rd or Lexington Avenues. What first caught my eye is that they leave a bowl of water and dog biscuits outside the restaurant every day. The second thing I noticed is that the neighborhood dogs who eat the biscuits all seemed trained to take only 1 or 2 and leave the rest for other dogs!
The drink menu offers an extended variety of frozen and non-frozen margaritas (think mango, strawberry, etc.) which are excellent. On the appetizer menu is the usual guacamole, but there is also a tasting plate, offering 3 different kinds of guacamole.
Dinner is expensive, but excellent - we had a sort of Mexican paella dish that we just couldn't get enough of. Waiters were excellent - great at recommending dishes, and seemed to have tasted everything on the menu to be able to speak from experience.
Could have been more of a selection for dessert, but after a meal that good, you don't need it.
If you go - check out the painting on the back-most wall - it looks like someone stopped in the middle and needs to come back to finish it. The waiters insist it's a finished project. (I had to ask.)