Huevos Rancheros

Preheat oven to 400º. In a large skillet over medium heat, heat oil. Add onions and cook until soft, 5 minutes. Season with cumin, chili powder, and salt. Add black beans and salsa to skillet and stir to combine. Sprinkle all over with cheese, then create four wells with a spoon and crack in eggs. Season with salt. Bake until egg whites are set and yolks still runny, 8 to 10 minutes. Plate on top of tostada. Garnish with avocado and cilantro, then drizzle with hot sauce and sour cream.