Hit a sandwich place. If you want a light meal, you can't beat a Subway sandwich where the main ingredient in a meat sandwich is bread n vegetables.
slightly off midtown. woorijip korean buffet. Food is mostly grab and go. There are lots of spots to sit too. I recommend jap chae (glass noodles with some veggie) for light meal.
If you're drinking, aren't you supposed to eat more to slow down absorption of alcohol ?