Add the chopped onion to the crock pot. Sprinkle the meat with cumin, paprika, coriander, garlic powder, and sea salt and gently rub into the meat with your hands. Place the meat in the crock pot and add the beer and lime juice. Secure the lid and cook 8 to 12 hours on low.
Transfer the meat to a cutting board and use two forks to shred it. Place the meat back into the crock pot to allow it to soak up the juices. Taste the carnitas for flavor and add more cumin, sea salt, and/or lime juice to taste.
Add the ingredients for the mango salsa to a bowl and toss well. Add more lime juice and/or sea salt to taste.
Load up bowls with desired amount of cooked rice or cauliflower rice, shredded pork, mango salsa, black beans, tomato, cilantro, and cabbage. Serve and enjoy!
*Omit the onion, garlic, and beer to make Low-FODMAP