Rinse beans. In a large saucepan combine beans and 4 cups cold water. Bring to boiling; reduce heat. Simmer 2 minutes. Remove from heat. Cover; let stand 1 hour.
Drain and rinse beans. Return beans to the saucepan and add 2-1/2 cups fresh cold water, the chicken broth, bay leaf, thyme, salt, and black pepper. Bring to boiling; reduce heat. Cover and simmer about 1-1/4 hours or until beans are tender, stirring occasionally. (Add more water if needed to prevent sticking or burning.)
Meanwhile, in a skillet cook bacon over medium heat until crisp. Drain on paper towels, reserving 1 tablespoon of bacon drippings in the skillet. Add onion, garlic, and crushed red pepper, if desired. Cook and stir over medium heat until onion is tender.
Add greens and tomato, if desired, to skillet. Cover and cook 1 to 2 minutes.
Drain beans, reserving liquid if desired. Discard bay leaf. Return beans to saucepan. Add onion mixture, tossing gently to combine. Season with additional salt and pepper. Spoon into serving bowl. Crumble bacon over top. Pass remaining broth. Makes 6 servings.