I can suggest some very nice places:
Prime at The Bentley- this may be perfect. It is described as follows: “he two-floor, rooftop-equipped penthouse pop-up gives the feeling that you’re in some glamorous NY-based movie that you can’t quite remember the name of, but definitely isn’t Crocodile Dundee, thanks to dangling orb chandeliers, gilded chairs, fractured mirrors for super-good luck, and massive floor-to-ceiling windows overlooking the East River and Queensboro Bridge.
The eclectic menu’s entirely kosher, but goes well beyond delicious matzoh while splitting into sea- and land-based choices. The latter counts unique sushi rolls with an Italian touch like the seared salmon w/ sun-dried tomato & truffle teriyaki sauce, as well as antipasti plates like toro tartare w/ wasabi olive oil, and lemon mustard aioli-topped, mirin-cured Irish “bio-salmon”, which was presumably harvested from the Pauly Shores.
Meanwhile, earth-eats come in the form of housemade Italian sausages in a blanket, fried artichokes w/ lemon aioli, Long Island duck sliders, and ribs w/ spicy Korean marinade known as the Bentley Rack, which is definitely allowed into the luxury cars in the UES.”
This place is under OU hashgacha, run by the Prime Grill people (considered the nicest kosher place in NYC for a while), and sounds perfect. The place has a view of the skyline and especially the 59th street bridge, which would be nicely illuminated at night. Sounds romantic to me.