1. Preheat the oven to broil and line a baking sheet with foil.
2. Brush tempeh with the tomato paste. Sprinkle with the oregano and season with salt and pepper.
3. Heat the oil in a small frying pan over medium heat. Add the tempeh and cook until brown, 2 to 3 minutes on each side.
4. Split the roll in half. Toast in the oven until just golden.
5. Assemble the sandwich on the baking sheet. Place the tempeh on the roll and top with sauce and cheese. Broil until cheese is melted (2-3 minutes), watching closely to avoid burning it.