01 - Pulse rolled oats in a food processor until coarsely ground. Add black beans, onion, garlic, bell pepper, cilantro, tomato paste, cumin, smoked paprika, chili powder, salt, and pepper; pulse until the mixture is combined but still chunky.
02 - Transfer mixture to a bowl and form into 4 equal-sized patties.
03 - Heat 1 tbsp olive oil in a nonstick skillet over medium heat. Cook patties for 5 to 6 minutes on each side until crisp and warmed through.
04 - Whisk vegan mayonnaise, minced chipotle, lime juice, and salt together in a small bowl until smooth.
05 - Toast burger buns if desired. Spread chipotle mayo on each bun half, then layer with lettuce, tomato slices, red onion, and black bean patty. Add pickles if using, and top with bun.
06 - Serve immediately while warm.