Wash and dry green beans, then cut off the tops on both sides of each bean, removing any tough strings. Bring a pot of water to a boil, season with salt and add green beans. Cook beans about 15 minutes or until tender enough, that you can easily stick a fork into the beans. Drain and cool, then place into a salad bowl.
Wash and dry tomatoes, then cut into slices, removing tough stems. Place into salad bowl.
Peel and thinly slice onion and add to salad bowl.
Assemble your balsamic dressing. Combine garlic, salt, pepper, olive oil and balsamic vinegar and mix well. Pour dressing over salad and combine. Serve.