1. Preheat the oven to 400°F.
2. Slice the English muffins in half and place on a baking sheet. Toast lightly in the oven if desired. Set aside.
3. Place the beef, red pepper, and oregano in a large nonstick skillet over medium-high heat and cook, breaking up the large pieces, until the meat is no longer pink, 6 to 8 minutes. Drain excess fat.
4. Add the pasta sauce and mix well.
5. To assemble the pizzas, top each muffin half with 1/12th of the meat mixture. Sprinkle the cheese evenly over the top of each.
6. Bake until the cheese melts, 5 to 7 minutes. Serve hot.