In a small bowl, combine the paprika, oregano, thyme, cayenne, garlic powder, onion powder and sugar. (You can omit this step and use your favorite packaged blackening spice mix.).
Pat catfish fillets dry with paper towels. Brush lightly with oil, then season well with salt and pepper. Sprinkle liberally with blackening spice mix, gently pressing spices onto fish to adhere.
Coat bottom of a large, non-stick frying pan with vegetable oil. Heat over medium-high heat until oil is shimmering. Add catfish and fry until cooked through, 3-4 minutes per side. Do not overcrowd pan. Work in batches and keep warm in a low oven.
Spread toasted rolls with tartar sauce. Place one fillet on each roll, then top with lettuce and tomato. Serve immediately.