In a small bowl, combine red peppers with oregano or fennel, salt and pepper. In a second bowl, combine cheeses. Set aside.
Cut each pita so that you have 4 flat rounds. Place the rounds, rough side up, on a baking sheet. Broil, being careful not to burn them, until golden brown around the edges, about one minute. Remove from broiler.
Distribute tomato sauce over each pita, spreading it to the edges. Top each pita with roasted red peppers. Sprinkle each with cheese, then add the onion in rings.
Broil again until cheese is melted and pizzas are hot, about two minutes.
Per serving: 137 calories, 7 g protein, 23 g carbohydrates, 3 g total fat (2 g saturated fat), 7 mg cholesterol, 3 g fibre, 475 mg sodium.