Heat 2 tablespoons oil in large pot on high. Brown beef, 5 to 7 minutes on both sides. Transfer to a plate. Preheat oven to 250 degrees with rack in the lower third of the oven. Sauté onion, peppers, garlic and salt (plus the other 2 tablespoons of oil if using flank steak), stirring and scraping bottom of pan until vegetables are golden brown, 3 to 5 minutes. Stir in wine and cook until evaporated. Stir in paprika, oregano, cumin, black pepper, and cayenne until vegetables are coated. Continue to cook until spices are fragrant, about 1 minute. Add tomatoes, and coarsely break up with a spoon. Bring to a boil and cook, stirring occasionally, until liquid reduces by half, about 5 minutes. Nestle roast into tomato mixture and tuck in bay leaves. Cover and transfer to oven until meat is very tender and shreds easily, 2 1⁄2 to 3 hours. Cool 15 minutes. Skim excess fat from sauce, discard bay leaves. Using forks, tear meat into sauce. Stir in olives and vinegar. Top with cilantro. Serve with rice, black beans and plantains sautéed in olive oil.