1 large onion, finely chopped
1 tablespoon olive oil
4 garlic cloves, minced
1 medium carrot, shredded
1 to 2 teaspoons chili powder
1 teaspoon ground cumin
1 can (15 ounces) pinto beans, rinsed and drained
1 can (15 ounces) black beans, rinsed and drained
1-1/2 cups quick-cooking oats
2 tablespoons Dijon mustard
2 tablespoons reduced-sodium soy sauce
1 tablespoon ketchup
1/4 teaspoon pepper
8 whole wheat hamburger buns, split
8 lettuce leaves
8 tablespoons salsa