Coat the bottom of a medium skillet with oil and place it over medium-high heat. Add the onion, hot pepper and garlic. Sauté until onions and peppers are slightly softened and browned in spots, about 3 minutes.
Add the seitan, black pepper, paprika, and salt. Continue to sauté until the seitan begins to crisp in spots, about 3 more minutes.
Divide the seitan mixture between sandwich rolls. Thin the sweet potato cheese with water until desired consistency is reached, and use it to top sandwiches, along with some ketchup.