Season the pork shoulder with salt, black pepper, cumin, and oregano.

Place the seasoned pork in a large pot with the quartered onion, minced garlic, orange juice, and chicken broth.

Bring the mixture to a boil, then reduce heat to low and cover the pot.

Cook for 4 hours, or until the pork is tender and easily shreds with a fork.

Remove the pork from the pot and shred it with two forks.

Serve the shredded pork in warmed corn tortillas with chopped cilantro, diced onion, lime wedges, and salsa if desired.