In a slow cooker, combine the diced tomatoes and their juices, the water, bell peppers, onion, garlic, jalapeño, oregano, cumin, and bay leaf. Add the flank steak, cover, and cook on HIGH for 4-5 hours, until the meat is very tender.
Transfer the meat to a cutting board and shred. Return it to the slow cooker.
Discard the bay leaf.
Add the olives, capers, and 1 tablespoon of the cilantro to the slow cooker. Stir it in.
Serve the ropa vieja with steamed rice. Garnish with remaining cilantro.