Cafe Luna is lovely at lunch time, with tapas at dinner. I haven't been for dinner in a while, but it was great when I went a couple of years ago. There's patio seating in nice weather, and an intimate dining room otherwise.
Cafe Luna is at the corner of 4th and Green in the funny wooden building - either go up the stairs from Green and turn to your left, or enter from the side entrance on 4th.