Wash the beans and soak overnight in cold water.
To make the meatballs: Place all the meatballs ingredients in a large bowl and mix well. Form 8 meatballs and set aside.
Drain the beans and place in a large pot and add the water. Over medium-high heat, bring the beans to a boil, then cover the pot and reduce the heat to medium-low. Add more water if needed. Add the meatballs and allow the beans to cook until almost tender, approximately 1 hour.
When the beans are cooking, prepare the guiso. In a large skillet, heat the vegetable oil over medium heat, add the tomatoes, onions, scallions, salt, pepper, garlic, cilantro and ground cumin and cook for 10 to 15 minutes.
Add the guiso, carrots and potatoes. Cover and cook for another 30 minutes or until the beans are fully cooked. (Add additional water as necessary).