Cook meat in water for 2 to 3 hours until meat is tender. Remove meat and cut in individual servings.
Combine vinegar, ají paste, ketchup, soy sauce, crushed garlic, salt and pepper and marinate meat for 2 hours. Remove meat and save marinade.
Cook potatoes in boiling water. Peel and half them.
Pour oil in a medium size skillet and fry meat on both sides.
Dip halved potatoes in marinade and carefully brown them in 2 or 3 tablespoons oil.
Serve meat with white rice, potatoes, onion creole sauce, and Soltero (see Fava Bean and Cheese Salad).