Heat oil over medium heat in a large sauté pan. Add onion and green pepper; cook and stir until transparent. Add garlic and sauté for an additional minute.
Lightly salt and pepper the meat cubes and dredge in flour. Add the meat to the pan and brown on all sides. Add the cumin, oregano, salt and pepper and cook for 3 minutes. Add wine, tomato sauce, vinegar, olives and bay leaves. Add just enough water or beef stock to cover the meat. Bring to a boil, reduce heat to low, cover and simmer until fork-tender, about 1-2 hours. Add more water if the stew becomes too thick.
Add potatoes and cook, covered, until potatoes are tender. Season with salt and pepper to taste. Serve hot with rice.