Cut the pork shoulder into large chunks, about 3-4 inches each.
In a large pot or Dutch oven, heat oil over medium-high heat. Sear the pork chunks until browned on all sides, about 8-10 minutes.
Add the onion, garlic, and spices (cumin, coriander, chili powder) to the pot and stir to combine.
Pour in the orange juice, lime juice, and water or chicken broth. Add bay leaves and a pinch of salt and pepper.
Bring to a boil, then reduce the heat to low. Cover and simmer for 2-3 hours, until the pork is very tender and shreds easily.
Once the pork is cooked, shred it using two forks. For a crispy finish, you can spread the shredded pork on a baking sheet and broil for 5-10 minutes to crisp up the edges.
Serve with tortillas and your choice of toppings.