Cut the flank steak into large pieces and place them in a large bowl. In a small bowl, combine the adobo and the Worcestershire sauce to make a paste. Rub the paste into the meat, add the beer, and let marinate for 15 minutes in the refrigerator.
Transfer the meat, as well as the marinade to the crock-pot and add the tomato paste and crushed tomatoes to the mix. Cook on low for about 7-8 hours or high for 5-6 (these are just estimates!). You’ll be able to easily tell when the meet is done because it will start falling apart easily.
During the last hour add the veggies to the slow cooker.
Remove the meat from the pot and shred the meat using 2 forks. To thicken the sauce you can add some cornstarch (dissolved in cold water first) or bump the temp up to high during the last part of the cooking. You could also leave out one of the beers.