Heat oven to 400°F. Place frozen biscuits on microwavable plate. Microwave uncovered on High 10 seconds; turn over and microwave 10 seconds longer or until biscuits are softened.
Sprinkle ungreased cookie sheet with cornmeal. Place each biscuit on cookie sheet. Press into 5-inch round. Using fork, prick entire surface of each. Bake 8 to 10 minutes or until golden brown.
In small microwavable bowl, microwave salsa uncovered on High 15 to 30 seconds or until hot. Stir in shrimp and cheese.
Place biscuit rounds on individual serving plates. Top each with half of lettuce, shrimp mixture and sour cream. Top with avocado slices. Serve immediately.