Trim fat from meat. If necessary, cut meat to fit in a 5- to 6-quart slow cooker. Place onion in slow cooker; top with meat. In a medium bowl, combine chili sauce, cola, ketchup, mustard, chili powder, vinegar, cumin, garlic, paprika, salt, black pepper, and crushed red pepper; pour over meat.

Cover; cook on low-heat setting for 12 to 13 hours or on high-heat setting for 6 to 6 1/2 hours.

Transfer meat to a cutting board; remove onion with a slotted spoon. Set cooking liquid aside. Thinly slice meat or pull apart with two forks; combine meat with onion.

Add enough of the reserved cooking liquid to moisten pork. (If necessary, return pork mixture to cooker. Cover and cook on high-heat setting for 15 minutes more to heat through.) Serve pork mixture on toasted buns, slider rolls, in a wrap, nacho, or on flatbread. If desired, top each sandwich with coleslaw.