Heat 2 teaspoons olive oil in a skillet over medium heat. Add the diced red onion and sauté until tender, about 4 minutes. Remove from heat and let cool slightly.
Make the Honey Dijon mustard by whisking together 2 tablespoons Dijon mustard and 3 teaspoons honey; refrigerate until ready to use.
In a large mixing bowl combine the cooked quinoa, cooked and drained brown lentils, diced green chilies, rolled oats, white whole wheat flour, cornstarch, panko bread crumbs, garlic powder, cumin, paprika, the sautéed onion, and salt and pepper to taste.
Mix thoroughly until the mixture holds together when pressed. Form into 4 evenly sized patties.
Heat 1 tablespoon olive oil in a large skillet over medium heat. Add the patties and cook until browned on both sides and heated through, about 10–12 minutes total, flipping once.
Serve the burgers on buns or rolls with Honey Dijon mustard and any desired toppings such as sautéed mushrooms, tomato, red onion, or romaine lettuce.