In a covered medium saucepan cook beans in boiling lightly salted water for 12 to 15 minutes or until crisp-tender; drain.
Meanwhile, in a large skillet cook the onion and garlic, covered, in hot oil over medium-low heat for 12 to 15 minutes or until onions are tender, stirring occasionally. Uncover; cook and stir over medium-high heat for 3 to 5 minutes or until onions are golden, stirring once or twice. Remove from heat.
Add the tomato, oregano, salt, and pepper to mixture in skillet. Stir in beans. To serve, transfer to a serving dish. Makes 4 servings.