In a large mixing bowl, combine the cooked black beans, grated yellow onion, minced garlic, diced chipotle peppers, adobo sauce, tamari, balsamic vinegar, ground cumin, sea salt, and black pepper. Mix until evenly distributed.

Gently mash the mixture until it holds together but remains slightly chunky.

Fold in the egg (or prepared flax egg) and panko breadcrumbs. Mix thoroughly until fully incorporated.

Form the mixture into 6 equal patties, each about 1/3 cup in size. Refrigerate if too wet.

Heat a cast-iron skillet over medium heat and brush it lightly with olive oil, or preheat your grill to 400°F.

Place the patties onto the hot skillet or grill, cooking each side for about 5 minutes until golden and crispy.

Remove the patties and place them on hamburger buns with your desired toppings.