Combine the flour, 1 teaspoon cumin, salt and pepper in a shallow container or on wax paper. Roll beef in seasoned flour. Heat oil in a large nonstick skillet on medium; brown meat on all sides. Transfer meat to slow cooker, cover.
Meanwhile, in the same skillet, add onions and garlic and cook 4 minutes or until onion is softened. Stir in remaining cumin to coat onions and cook 1 minute. Add tomatoes and crush larger pieces. Bring to boil; stir in tomato paste, red wine and bay leaf. Bring to a simmer and stir. Pour mixture over beef. Cover and cook on low 8 hours; turn after 4 hours if possible.
Remove beef from sauce to platter and tent with foil. Turn cooker heat to high and cook 10 to 15 minutes to reduce sauce. Remove bay leaf. Slice meat and spoon some sauce over meat before serving.