Place bacon in a large skillet and cook over medium-low heat, turning occasionally, until evenly browned, about 5 minutes. Drain bacon bits on paper towels.
Preheat an outdoor grill for medium heat, 300 degrees F (150 degrees C) to 325 degrees F (165 degrees Fahrenheit). Lightly oil the grate.
Separate ground beef into 1/4-pound portions. Mix bacon and green onions in a bowl and press onto either side of ground beef, working it in until mixture has an even consistency. Shape mixture into patties. Mix garlic salt and ground black pepper in a bowl and rub on both sides of the patties. Press a small indentation into the center of each patty.
Place burgers on the preheated grill and pour 1/2 tablespoon of steak sauce into each indentation. Grill burgers for 5 minutes. Flip and add 1/2 tablespoon of steak sauce to the center of each burger. Top each with a slice of Cheddar cheese and grill until cheese is melted and burger has reached desired degree of doneness, about 4 minutes. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).
Meanwhile, begin toasting hamburger buns on the grill rack.
Remove burgers and buns from the grill once the cheese has melted. Assemble burgers.