Heat oil in large skillet over medium-high heat. Add garlic, ginger, scallion and chile. Cook 30 seconds. Add pepper and water chestnuts; cook for 2 minutes.
Stir in shrimp, sherry, soy and oyster sauces. Cook 4 minutes, stirring occasionally. Remove from heat; drizzle sesame oil on top. Serve on lettuce pieces with hoisin. Makes 4 servings.