Place the sliced onion and minced garlic in the bottom of the slow cooker to create a base layer.
Set the pork shoulder on top of the onions and season it evenly with the salt, black pepper, and cumin.
In a bowl, mash the chopped mango with the minced habanero, brown sugar, and apple cider vinegar until the mixture forms a chunky sauce.
Pour the mango habanero sauce over the pork, making sure it coats the meat on all sides.
Cover the slow cooker and cook on low for 8 hours until the pork pulls apart easily with a fork.
Shred the pork directly in the slow cooker using two forks, then stir it through the remaining sauce to absorb the flavors.
Spoon the pulled pork onto the slider buns and serve while warm.