Combine Ground Beef, jalapeño, onion, cilantro, salt and black pepper in large bowl, mixing lightly but thoroughly. Lightly shape into four 1/2-inch thick patties.
Place patties on grid over medium, ash-covered coals. Grill, covered, 8 to 10 minutes (over medium heat on preheated gas grill, covered, 7 to 9 minutes) until instant-read thermometer inserted horizontally into center registers 160°F, turning occasionally.
Place each burger on lettuce. Evenly top with onion, tomato and avocado. Wrap lettuce around burgers.
Nutrition information per serving: 263 Calories; 125.1 kcal Calories from fat; 13.9 g Total Fat; 3.9 g Saturated Fat; 0.1 g Trans Fat; 0.4 g Polyunsaturated Fat; 3.3 g Monounsaturated Fat; 84 mg Cholesterol; 151 mg Sodium; 9.3 g Total Carbohydrate; 3.1 g Dietary Fiber; 2.7 g Total Sugars; 28 g Protein; 0 g Added Sugars; 35.5 mg Calcium; 3.8 mg Iron; 776 mg Potassium; 0 mcg Vitamin D; 0.2 mg Riboflavin; 6.6 mg NE Niacin; 0.5 mg Vitamin B6; 2.8 mcg Vitamin B12; 250 mg Phosphorus; 6.6 mg Zinc; 21.2 mcg Selenium; 102.2 mg Choline;