2. Meanwhile, in nonstick 12-inch skillet, heat oil over medium heat until hot. Add onion and cook 5 to 7 minutes or until tender and lightly browned. Stir in tomatoes with their juice, crushed red pepper, and oregano; heat to boiling over high heat, breaking up tomatoes with side of spoon. Reduce heat to medium and cook 7 minutes to thicken slightly. Stir in shrimp, and cook 3 to 4 minutes or until shrimp turn opaque throughout. Remove skillet from heat; stir in chopped parsley and 1/2 cup crumbled feta.