In a small bowl, mix all the spices together, garlic powder, cumin, chili powder, onion powder, oregano, salt and pepper. Set aside.
Cut the pork shoulder into large chunks. Rub the meat with the spice mix thoroughly, making sure each piece of meat is fully covered. In a large skillet or a dutch oven, heat some oil and sear the meat on all sides. Make sure you don't crowd the pan, it's best to do it in batches. You want to sear the meat until it has a nice brown color on it.
Chop up the onion in big pieces and place it at the bottom of the crockpot, followed by the bay leaves and cinnamon stick.
Add the meat on top of the onion in the crock pot, pour the beer and orange juice and cook on low for about 6 to 8 hours.
After about 8 hours remove the meat from the crockpot with a slotted spoon and place it on a baking sheet lined with aluminum foil.
Take 2 forks and start shredding the meat into smaller pieces. Pour some of the leftover liquid over the meat.
Place the meat under the broiler, for about 5 to 10 minutes, you should watch it though, each oven is different and you don't want to burn it. Take the meat out, flip it over the other side using a spatula and then place it under the broiler again for another 5 minutes or so. You want to make sure that it's nicely browned.
Serve on tacos, burritos, tamales, sandwiches, etc.