Rinse beans. In a large saucepan, combine beans and enough water to cover. Bring to boiling; reduce heat. Simmer for 2 minutes. Remove from heat. Cover; let stand for 1 hour. (Or, skip boiling water and soak beans in a large saucepan. Cover; set in a cool place for 6 to 8 hours or overnight.)
Drain beans in colander; rinse. Return beans to saucepan. Stir in onion, garlic, bay leaf, parsley, salt, and crushed red pepper. Stir in 3 cups fresh water. Bring to boiling; reduce heat. Cover and simmer for about 1-1/2 hours or until beans are tender, adding more water, if necessary, and stirring occasionally.
Meanwhile, cook sweet potato in boiling salted water to cover for 15 to 20 minutes or until tender; drain.
Remove bay leaf from beans; discard. Add tomatoes to bean mixture. Uncover and simmer, stirring occasionally, for 15 to 20 minutes more or until a thick gravy forms.
Stir in orange peel. To serve, spoon beans over hot rice. Sprinkle with shredded kale, spinach, or flat-leaf parsley, if desired. Makes 4 servings.