The New York Deli is a counter-service eatery that serves up American sandwich favorites like sliced turkey, a Ruben, and even smoked salmon on a bagel (and bagels are not that easy to find in Japan). The sandwiches are not the massive affairs you'll find at NY-style delis back in the USA, and are lacking boldness in flavor (likely designed that way to appeal to the Japanese palate). Still, they're good, and if a turkey sandwiching is what you're craving (or just need a quick bite), this is the place.
There's ample seating here, although it's not obvious where it all is. A lot of it is in a room that's to the right and around a corner from the front entrance of the restaurant. If you can't find a seat, keep looking because chances are there is one available somewhere nearby.