Heat vegetable oil in a large skillet over medium-high heat. Add diced onion and cook for about 5 minutes until translucent.

Add minced garlic to skillet and cook for another minute until golden and aromatic.

Season pork shoulder with salt, pepper, smoked paprika, chili powder, and cumin. Rub spices into meat.

Transfer onion and garlic mixture into the bottom of the crockpot. Place the seasoned pork on top.

In a bowl, mix barbecue sauce, apple cider vinegar, brown sugar, and Worcestershire sauce until blended.

Pour the sauce mixture evenly over the pork in the crockpot, ensuring it's well-coated.

Cover crockpot and cook on low for 8 to 10 hours or high for 4 to 5 hours until fork-tender.

Remove pork from the crockpot, let rest for a few minutes, then shred with two forks.

Return shredded pork to the crockpot, mixing with remaining juices.

To serve, add cooked rice or quinoa to each bowl, top with shredded pork, coleslaw mix, and green onions.