Soak the pig's tail overnight in fresh water to cover. Then thoroughly rinse the pig's tail (or ham hocks) in cold water. Combine in a large heavy sauce pan with the beef, dried kidney beans (if using canned beans don't add at this time), and the water. Cover and cook over medium heat for about 1 hour, until the meat and beans are tender. Add the potatoes, coconut milk, and any other peeled root vegetables or dumplings along with the onion, scallions, thyme and hot pepper. (If using canned beans, add at this time.) Add salt to taste. Stir the soup and allow to simmer for 1 hour. Remove the whole hot pepper and thyme sprig before serving. Serve hot. This is even better served the second day.