Cook the rice using your preferred method.
Heat pan over medium heat. Add raw walnuts and toast for 5-7 minutes, stirring frequently, until fragrant and golden brown. Remove from pan and allow to cool.
Heat vegetable oil in the same pan over medium heat and add onion. Season with salt and pepper and sauté for 3-4 minutes, or until onion is fragrant, soft, and translucent. Remove from heat and set aside.
Add cooled walnuts to blender or food processor and blend until a fine meal is achieved. Set aside.
Add black beans to a large mixing bowl and mash well with a fork, leaving only a few whole beans, next add cooked rice, walnut meal, sautéed onion, spices, bread crumbs, BBQ sauce and sugar.
Mix thoroughly until a moldable dough forms. If dry, add extra 1-2 Tbsp BBQ sauce. If too wet, add more bread crumbs. Taste and adjust seasonings as needed.
Divide into 10 equal portions and form into patties (approx 1/3 cup each)
Heat a greased pan or BBQ and cook patties for 5 mins both sides.