Preparation Bring broth and ham hocks to boil in large pot. Cover, reduce heat to medium-low and simmer 15 minutes. Add diced potatoes, tomatoes with juices, onion, carrots, celery, barley, and oregano. Bring to boil. Reduce heat to medium-low; simmer uncovered until meat and barley are tender, about 1 hour. Using tongs, remove ham hocks from soup. Cut meat off bones and chop coarsely. Return meat to soup; discard bones. (Can be prepared 2 days ahead. Refrigerate uncovered until cold, then cover and refrigerate. Bring to simmer before continuing.) Add green beans; simmer until beans are tender, about 15 minutes. Season soup to taste with salt and pepper.