Heat olive oil in a skillet over medium high heat. In a small bowl, combine salt, five spice powder, garlic powder, paprika and pepper. Rub spice mixture on the outside of the pork then place in the skillet. Cook for 2-3 minutes on each side, until golden brown, then place in the slow cooker.
Pour 1⁄2 cup water in the bottom of the slow cooker then cover and cook on low for 6-8 hours.
In a large mixing bowl, combine all pickled vegetable ingredients; cover and store in the fridge until serving. In a small bowl, whisk together all aioli ingredients until well combined; cover and store in the fridge until serving.
When pork is done cooking, shred it with two forks then serve on a bun (4.1 ounces of pork each). Top each sandwich with 2.5 ounces of slaw and 0.5 ounce of aioli.