Divide the beef in half. On a sheet of waxed paper, shape each half into a 4″ patty. Season both sides with salt. Transfer the waxed paper to a plate. Place, uncovered, in the freezer for 5 minutes.
Preheat a large nonstick skillet over medium-high heat until drops of water sizzle when splashed on the pan. Place the patties in the pan. Cook for 1 to 2 minutes per side, or until no longer pink. Meanwhile, place the bun top and bottoms, cut-sides down, in the pan. Cook for about 1 minute, or until toasted. (If the pan is not large enough to hold the patties and the buns, first cook 1 patty with the bottom bun and then start assembling the sandwich while the others cook.) Just before the patties are cooked, place the cheese on 1 patty.
Place 1 bun bottom on a plate. Spread on 1 tablespoon sauce. Place the cheeseburger, cheese-side down, on the bun. Spread 1 teaspoon sauce on the second bun bottom and place, sauce-side down, on the cheeseburger. Top with the remaining 1 tablespoon sauce, the onion, lettuce, pickles, the remaining burger, and the bun top.