Heat the oven to 425°F and oil a rimmed sheet with the teaspoon oil. Gently mix pork, mashed beans, cornmeal, egg, onion, cumin, oregano and meatball salt. Form 24 meatballs and bake for 18 to 22 minutes until the centers reach 160°F.
Meanwhile, heat sauce oil in a saucepan over medium heat. Stir in flour and ancho powder for 30 seconds, then gradually whisk in broth, crushed tomatoes and sauce salt; simmer for 4 minutes until smooth.
Transfer hot sauce and hot meatballs to a 4-quart slow cooker. Cover and cook on HIGH for 2 hours, turning gently once, until the centers reach 165°F.
During the final hour, bring brown rice, rice water and rice salt to a boil. Cover and cook on low for 40 to 45 minutes until tender and the water is absorbed, then rest off heat for 10 minutes.
Scatter cheddar over the meatballs, cover with the cooker off for 5 minutes until melted and avoid stirring the cheese into a paste. Divide rice among 6 bowls and add 4 meatballs and sauce to each.