Preheat oven to 400°F. Combine sausage, mozzarella cheese, green pepper, onion, ⅓ cup pizza sauce and garlic powder in large bowl.
Beat egg and water in small bowl with wire whisk or fork until well blended. Press or roll out each biscuit on lightly floured surface to 5-inch circle. Spoon rounded 2 tablespoons sausage mixture onto center of each biscuit. Brush edges lightly with egg wash; fold in half. Press edges together to seal. Place on baking sheet sprayed with cooking spray. Brush tops with remaining egg wash; sprinkle with Parmesan cheese and oregano.
Bake 10-12 minutes or until golden brown. Meanwhile, heat remaining pizza sauce.