Slow-Cooker Ropa Vieja

1 15-ounce can crushed tomatoes
3 tablespoons ketchup
1 tablespoon apple cider vinegar
2 cloves garlic, minced
1 1/2 teaspoons ground cumin
1 jalapeno pepper, thinly sliced (with seeds)
Kosher salt
1 1/2 pounds skirt steak or flank steak
2 bell peppers (1 red, 1 green), sliced 1/2 inch thick
1 small onion, thinly sliced
3 tablespoons chopped pimento-stuffed green olives, plus 1 tablespoon brine from the jar

Cooked white rice, for serving

Combine the tomatoes, ketchup, vinegar, garlic, cumin, jalapeno and 3/4 teaspoon salt in a 5-to-6-quart slow cooker. Add the steak, bell peppers and onion and toss to coat. Cover and cook on low, undisturbed, 8 hours.
Uncover and skim off any excess fat. Coarsely shred the meat with 2 forks, then stir in the olives and olive brine. Serve over rice.

Source: Food Network