1Heat charcoal or gas grill. In medium bowl, mix all burger ingredients except cooking spray. Shape mixture into 6 patties, about 1/2 inch thick. Spray patties with cooking spray, or lightly brush with oil.
2Place patties on grill over medium heat. Cover grill; cook 11 to 13 minutes, turning once, until meat thermometer inserted in center of patties reads 160°F.
3Spread 1 tablespoon mayonnaise on bottom of each burger bun. Top each with lettuce, bacon, burger, avocado, tomato slice and bun top.