Place the roast right in the slow cooker. (You can brown it if you like but not necessary if you are short on time.)
Add 1 large sliced onion, 1 tablespoon of cumin, 1 teaspoon of chili powder, 1 tablespoon of dried oregano, 1-2 chipotle peppers in adobo sauce for medium or hot, juice of 2 limes, 1/2 cup orange juice (or juice of 2 oranges,) 2 tablespoons minced garlic, 1 teaspoon onion powder, 3 bay leaves, salt and pepper.
Set the slow cooker to 8 hours and walk away!
When the beef is falling apart, shred it in the slow cooker.
Serve with warmed soft corn or flour tortillas, and for easy preparation, top simply with chopped onion & fresh cilantro. If you want to take it to the next level, serve in your favorite tortillas and top with a cilantro lime coleslaw. (Substitute lime juice for the vinegar, and add chopped fresh cilantro and a finely chopped jalapeño & red pepper.) The creaminess and crunch of the coleslaw are so good with the beef!