Bring water and crab boil to a boil in a large skillet. Add shrimp; cook 3 minutes or until done. Drain and rinse under cold water. Chill.
Combine shrimp, cilantro, lemon juice, salt, banana pepper, and beans in a large bowl. Arrange 3 tomato slices and 4 avocado wedges on each of 4 plates; top each serving with 1 cup shrimp salad.