1. In a small bowl, combine onion powder, ginger, sugar, cumin, allspice, cayenne pepper and salt. Rub pork with sesame oil, then rub spice mixture into pork.
2. Heat canola oil in a large stainless steel skillet over medium-high heat. Brown pork on all sides, about 3 minutes per side. Transfer to slow cooker. Whisk 1/4 cup of the hoisin sauce with 1 cup water. Pour around pork in slow cooker. Cover and slow cook on HIGH for 41/2 hours or LOW for 6 hours.
3. Remove pork to a large bowl. Shred with 2 forks into large pieces and toss with remaining 1/2 cup hoisin sauce.Slaw
4. In a large bowl, combine rice vinegar, sugar, salt and pepper. Whisk in canola oil and sesame oil. Toss with coleslaw mix.
5. To serve, microwave tortillas for 30 seconds or until heated through. Spread each tortilla with a little additional hoisin sauce, if desired. Top with slaw and shredded pork. Fold up and serve.