Gather all ingredients.
Preheat the oven to 425 degrees F (220 degrees C). Coat an 8x8-inch baking dish with cooking spray. Heat oil in a large skillet over medium-high heat. Add onion, bell pepper, and jalapeño; cook, stirring occasionally, until softened and slightly browned, 5 to 7 minutes.
Stir in beans, picante sauce, water, salt, cumin, cayenne pepper, and smoked paprika. Mash beans using the back of a spoon or a potato masher until mixture is slightly thickened. Bring to a simmer over medium-high heat. Simmer, undisturbed, until sauce thickens and bubbles appear all over the surface, 5 to 7 minutes. Stir in corn.
Transfer mixture to the prepared baking dish, and sprinkle with tomato, Monterey Jack cheese and Cheddar cheese. Cover with aluminum foil.
Bake in the preheated oven until casserole is hot and cheeses are melted, 25 to 30 minutes. Sprinkle with green onions. Let cool slightly before serving.
Serve with lime wedges, cilantro, sour cream, salsa, warm tortillas, or tortilla chips, if desired. Enjoy!