Preheat the oven to 400 degrees F (200 degrees C).
Prick potatoes a few times with a fork. Rub potatoes with 1 teaspoon oil and set directly on the oven rack. Bake for 1 hour. Transfer to a cutting board and let cool until easily handled. Keep the oven on.
Cut the potatoes lengthwise and scoop out flesh to within 1/4 inch of skin. Brush remaining oil over the skins and sprinkle with salt. Place them on a baking sheet skin-side down and bake for 5 minutes.
Meanwhile, combine black beans, corn, picante sauce, jalapeno, onion, lime juice, and cumin in a bowl. Stir until evenly combined.
Divide filling between the potatoes and top with Cheddar cheese. Bake until cheese has melted, about 5 minutes.