Mix ingredients for burgers thoroughly and shape into burger patties, pressing a divot into the center of each.
Grill onions on a grill sheet until caramelized.
Grill pineapple slices sprinkled with a little bit of brown sugar until browned.
Grill burger patties until cooked as well as you like them, basting with teriyaki sauce.
Build burgers on buns with melted Swiss cheese, a pineapple slice and some of the onion.