Heat grill to medium-high heat.

Make the Tamari Glaze: combine tamari, maple syrup and red pepper flakes. Set aside.

On a well-seasoned, clean grill, cook the burger patties for 5 minutes. While cooking, add a small amount of glaze to the top of the burger with a brush. After 5 minutes, flip the burgers and generously glaze the second side. Cook for an additional 5 minutes (or until the burgers reach your desired temperature), flip again and glaze once more. Set burgers aside to rest.

Add pineapple slices to the grill and cook 2-3 minutes per side. Toast buns on the grill for 30 seconds to 1 minute.

Build each burger: add 1 tablespoon of mayonnaise to the top bun. On the bottom bun add butter lettuce, burger patty, pineapple slice, ¼ cup kimchi and avocado slices. Place the top bun on the bottom and repeat the process for remaining three burgers.