Place the flank steak in a plastic bag and add the garlic, scallions, onion, cumin, salt and pepper. Refrigerate for about 2 hours.
In a medium pot, place the flank steak and water and bring it to a boil over medium-high heat. Reduce the heat to medium-low and cook the beef for about 1 hour or until the beef is cooked.
Remove the beef from the water and set aside to let it cool. You can save the water used to cook the beef to make soup or just as a beef stock for other dishes.
Cut the beef into chunks and place in a food processor. Process until the beef is of a powdered consistency.