Soak the dried chilies in hot water for about 15 minutes until soft. Drain, and blend with onion, garlic, and tomatoes until smooth.

In the slow cooker, place the beef and pour the chili mixture over it. Add the broth, vinegar, oregano, cumin, bay leaves, salt, and pepper.

Cover and cook on low for 8 to 10 hours until the beef is tender and easily shreds.

Remove beef, shred into bite-sized pieces, and return to the pot to soak up the flavors.

Heat oil in a skillet, dip tortillas in the fat from the broth, and fry until crispy and golden on both sides.

Fill crispy tortillas with shredded beef, fold, and fry for another minute to crisp the edges.

Serve the tacos with the broth for dipping, and add toppings like cilantro and diced onions as desired.