Place sauce ingredients into a bowl, mix well, cover and reserve for later.
Cut eight parchment squares, each 4 inches by 4 inches. Divide beef into eight 3-oz. balls. Heat a flat top grill or barbecue to high and lightly oil it.
Place balls on the flat top, top each with a parchment square and use a large metal spatula, burger press, or bottom of a pot to press down evenly until patty is ¼-inch thick. Remove parchment and season patties with salt.
Cook patties for 2 minutes, then flip and top with a slice of cheese. Cook for another 2 minutes, then remove from heat. Their internal temperature should be 71°C (160°F).
Spread rink sauce on both sides of each bun. Add shredded lettuce to bun bottoms. Add two smash burger patties to each bun and serve promptly.
