Prepare marinade by combining the oregano, sour orange juice, chopped garlic, and oil, to taste. Let marinade stand for 1 hour.
With a very sharp knife, cut ham across lengthwise, exposing the bone. Cut around the bone around to remove it. Use small cuts to butterfly the ham, so it lies flat. Trim into a rectangular shape. Discard any excessive fat. Season the meat with marinade and set aside, refrigerated, for at least 2 hours.
Preheat oven to 375 degrees F.
Place rice stuffing in the middle of ham and fold both ways until stuffing is fully covered. Tie with string both lengthwise and across.
Place in a roasting pan and cook for 20 minutes per pound or until inside cavity reaches 150 degrees.
Black Beans and Rice (Moros y Cristianos):
Bring beans, 5 cups water, bay leaf, and 1/2 piece of Italian pepper to a full boil. Simmer until beans are soft. Strain and remove the pepper. Reserve the water (if necessary, add water to make 4 cups).
Saute the onion, pepper, garlic, and oregano in olive oil until translucent. Add the rice, beans, and water and bring to a boil. Season with salt. Reduce heat and cook covered until rice is soft.
Saute crushed garlic cloves in the 4 tablespoons of olive oil until brown. Remove the cloves and add to the rice. Season with vinegar and let stand.