1Heat gas or charcoal grill. In large bowl, mix beef, green onions, salt and pepper. Shape mixture into 4 patties, about 1/2 inch thick.
2Place patties on grill over medium-high heat. Cover grill; cook 8 to 12 minutes, turning once, until meat thermometer inserted in center of patties reads 160°F. Top each burger with 1 tablespoon barbecue sauce and 1 slice cheese. Cover grill; cook about 30 seconds longer or until cheese begins to melt.
3Remove burgers from grill; cover to keep warm. Place buns, cut sides down, on grill. Cover grill; cook about 1 minute or until golden brown.
4On bun bottoms, layer lettuce and tomato. Top with burgers and French-fried onions. Cover with bun tops.