Remove string and most of the fat from the pork roast.

Combine vegetable oil, paprika, pepper, cumin, coriander, salt, and garlic in a small bowl to create a paste.

Rub the paste all over the pork.

Cover the pork with cling film and marinate overnight in the refrigerator.

Transfer the marinated pork to a slow cooker.

In a separate bowl, mix ketchup, vinegar, brown sugar, water, and mustard.

Pour the ketchup mixture over the pork in the slow cooker.

Cook on low heat for 4 to 8 hours, or until the pork is very tender.

Remove the cooked pork from the slow cooker and place it in a large bowl.

Use two forks to shred the pork into long strands.

Remove 90ml of the cooking juice from the slow cooker and strain it into a saucepan.

Whisk in cornstarch to the strained cooking juice.

Bring the mixture to a boil while stirring.

Continue stirring until the sauce thickens and bubbles.

Return the shredded pork to the slow cooker.

Stir the pork to combine it with the remaining cooking juice.

Serve the pulled pork on soft rolls, drizzled with the thickened sauce.

Top with chilled tangy coleslaw.