Combine ketchup, brown sugar, ground cumin, ground cinnamon, chipotle pepper, ground pepper, salt, and apple juice in a small saucepan. Bring to a boil. Stir to dissolve brown sugar and allow sauce to thicken slightly. Turn off stove.
Place sirloin roast in slow cooker insert. Pour prepared sauce over pork in slow cooker insert. Cover and cook on low for 8 hours.
Half way through cooking, turn the pork.
Remove the pork to a plate. Leave the sauce in the slow cooker insert to keep warm. Shred pork with 2 forks. Return shredded pork to the slow cooker. Mix with sauce.
Mound pulled pork onto bottom of buns. Top with some coleslaw and cover with bun tops.