Pour lime juice into blender. Cover and turn on. Drop in chilies and, when finely chopped, turn off and add avocado and cilantro. Process until smooth. Thin to creamy consistency with water, about 2 to 3 tablespoons. Taste and season with salt, about 1 teaspoon.
3
Mix dressing with shrimp mixture. Cover with plastic wrap directly on surface of salad and refrigerate.
4
Serve with additional sprigs of cilantro. Best eaten within an hour or two of being made.