Load up your food processor with the walnuts, chopped onion, garlic, and mushrooms. Pulse until you have an evenly chopped mixture.
Heat a saute pan over medium-high heat and add a teaspoon of oil. Transfer the mushroom walnut mixture to the pan, and fry, while stirring, for 7-9 minutes. While that’s cooking, grind the black beans in the food processor until they are coarsely chopped.
Remove the pan from the heat and allow the mixture to cool for several minutes before stirring in the bread crumbs, the chopped black beans, the Worcestershire, liquid smoke, hoisin sauce, black salt and the flax egg. Mix well to combine, and chill the burger mixture for 30 minutes to an hour.
Divide the mixture into six portions, and form into patties. You might need to wet your hands for this part so the mixture doesn’t stick to your hands.
Take pineapple rings out of the can. Mix sugar, soy and teriyaki together and dip pineapple in mixture, make sure both sides are saturated and set on a plate for grilling. Grill on each side for 3- 4 minutes.
Add a drizzle of oil to a large nonstick or cast-iron pan, and heat on medium. Alternatively, grill at 375. Brush patties with teriyaki sauce. Cook for 4-5 minutes on one side, then flip them and cook for another 3-4 minutes on either a grill or skillet.
Dress up your bun of choice with whatever toppings you desire, and enjoy!!