Season the Pork: Rub the pork shoulder with cumin, smoked paprika, chili powder, salt, and pepper.
Assemble in Slow Cooker: Place the pork in the slow cooker. Add onion, garlic, jalapeños, and pineapple around it.
Prepare the Sauce: Whisk together soy sauce, apple cider vinegar, and brown sugar. Pour over the pork.
Cook: Cover and cook on low for 8-10 hours or on high for 5-6 hours, until the pork is tender.
Shred and Serve: Shred the pork with two forks and mix it with the sauce. Serve hot.