Spray the inside of the slow-cooker with cooking spray and turn it to desired heat.
The pork only needs a thin fat-cap, so trim any thick patches of fat away.
In a small bowl, combine salt, black pepper, oregano, cumin, chili powder and cinnamon. Mix thoroughly and rub the spice mix all over the pork.
Place the pork in the slow cooker and top with onion, garlic, bay leaves, green chilies and sangria.
Squeeze the juice from the oranges over the pork and add the orange fruit quarters to the cooker.
Cover and cook on LOW for 5-7 hours or on HIGH 4-6 hours.
When meat is fork tender, transfer the pork to a cutting board. Allow the pork to rest 10 minutes, and shred it by pulling it apart with two forks.
Strain the cooking juices into a small-medium stovetop pan. Bring to a boil over HIGH heat then reduce the temperature to MEDIUM. Cook until juices are reduced and thickened, approximately 15-20 minutes, depending how much liquid you have.
While pork is resting, preheat oven to 450°F and cover two cooking sheets with foil. Spray the foil with cooking spray.
Transfer the cooked pork between the two cooking sheets, in an even layer, and drizzle the pork with ½-¾ cup cooking juices per pan of pork. Cook 10 minutes or until liquid has evaporated then BROIL to desired crispiness. Watch closely so pork doesn’t burn.
When ready to serve, drizzle with additional reduced juices.
Serve as tacos, quesadillas, enchiladas or tostadas and top with your favorite taco toppings and peeled orange slices. Use your imagination.