In 4-quart saucepan, place steamer basket. Add 1 cup water; heat to boiling. Add green beans to basket. Cover; cook 4 to 5 minutes or until crisp-tender.
In 12-inch skillet, heat oil over medium heat. Add green beans, tomatoes, oregano, salt and pepper. Cook 30 to 60 seconds or just until tomatoes are heated. Sprinkle with cheese.