I don't think "tapas" when I think of NOCA, but the new "Bar Bites" Thursdays are all about the small plates -- that is, if you get a reservation to sit at the counter, and if they're not doing a special tasting menu that night. It's a fun way to get a sense of what the kitchen is up to, without necessarily committing to a drawn-out, multi-course meal (though the regular menu is still available). A couple items ($8-15) and a glass of vino would treat you just fine.
Here's the new menu for June 18: