Stir together olive oil, lemon juice, olives, tomatoes, red pepper, red onion, garlic, oregano, and feta cheese in a large bowl. Let stand at room temperature for 1 hour.
Bring a large pot of lightly salted water to a boil. Add the orzo and cook for 8 to 10 minutes or until al dente; drain and toss the tomato mixture. Sprinkle with chopped parsley to serve.
