Begin by sauteing the onions and olive oil in a frying pan over medium heat. Allow them to caramelize a bit and soften before placing in the crockpot.
Add the onions, pork, BBQ sauce and water to the crockpot. Set on low for four hours.
Mix the dressing ingredients for the coleslaw and toss with the thinly sliced vegetables. Allow the coleslaw to rest in the refrigerator for at least an hour. Toss before serving.
Layer the pulled pork and coleslaw on a bakery fresh bun and serve.