1. In a medium pot, heat oil over medium-high. Add onion and bell pepper; season with salt and cook, stirring, until tender, 6 to 8 minutes. Add cumin and chile powder; cook until fragrant, 1 minute. Add marinara, 2 cups water, and both beans; bring to a boil. Reduce to a simmer and cook, stirring occasionally, until slightly thickened, about 25 minutes. Season with salt and pepper. Serve, topped with avocado, cilantro, chile peppers, and sour cream.