253 Washington St., Union Square, Somerville
Diners gather at Casa B for Caribbean flavors and Latin flair in a romantic atmosphere. Cozy up on a couch downstairs for refreshing mojitos, and a trio of ceviche scooped up with crispy plantain chips. Happily, you can make a reservation here, which we noted after arriving one Wednesday evening, only to be told every seat was booked for the night. One feature many tapas restaurants share (besides serving shareable plates) is an open kitchen. No matter how crazy and crowded it gets, the cooks always appear to keep their cool.