Rinse green beans; remove and discard ends and any strings. In a 6- to 8-quart pan over high heat, bring about 3 quarts water to a boil. Add beans, cover, and cook until tender-crisp to bite, 4 to 5 minutes. Drain beans, pour into a serving dish, and keep warm. Dry pan.
Meanwhile, rinse tomatoes; remove and discard stems. Set pan over high heat and add olive oil, garlic, tomatoes, and basil. Stir until tomatoes are hot, about 3 minutes. Pour over beans. Add salt and pepper to taste.