Preheat your oven to 300 degrees.
Start by placing your pork in a large dutch oven. Add the orange juice, water, and 1tsp of salt.
Place your dutch oven in the oven and cook for about 2 1/2 hours.Then set aside to cool.
Place your chiles in a bowl and cover them with hot water. Let them soak for about 15 minutes until they've softened.
Place the chiles, 1 1/2 cups of their soaking liquid, onion, garlic, parsley, oregano, cumin, 1/4 tsp salt, pepper and vinegar in a blender and blend until smooth.
Once the pork has cooled, shred it using two forks and set it aside along with any of its juices.
In the large dutch oven, heat the oil over medium heat. Pour in the chile puree and bring to a simmer. Simmer for about 8-10 minutes. Stirring often until it thickens and darkens.
Add in the shredded meat and 1 cup of its juices and cook for about 20-25 minutes until the meat has absorbed all of the juice. Make sure to taste for salt.
Serve on a warm tortilla with your favorite fixings.