Ceviche is a peculiar twist on the Crock-Pot: scraps of raw fish cooked slowly, not with heat but with lemon or lime juices. La Calle Doce's ceviche is a tight, focused arrangement--a tiny still life--with a cupped lettuce leaf spilling over with avocado chunks, chopped tomato, scallion and opaque creamy-white chunks of fish and shrimp. It strikes the palate like a laser, searing the tongue and scorching the roof with tightly focused acid layers that gently unravel into briny sweetness. Leftover juices don't pool; they puddle once the debris is evacuated, leaving a fluid that might serve as a foundation for a killer margarita.