Toss the onions with 1 tablespoon of BBQ sauce. Allow to marinate for at least 20 minutes.
Meanwhile, make the coleslaw. whisk together mayonnaise, apple cider vinegar, garlic powder, salt and pepper. Pour over shredded cabbage and toss to combine. Cover and refrigerate until ready to use.
Once onions have marinated, place flour in a resealable plastic bag, add in onions and shake to coat.
Heat 1/4 inch layer of oil in a skillet over medium heat. Once hot, remove onions from flour and shake off any excess. Fry in hot oil until golden brown and crunchy. Use a slotted spoon to transfer to a paper towel lined plate. Sprinkle with salt.
Heat a grill to medium-high heat and cook hot dogs until cooked through.
To assemble a hot dog: place a hot dog in a bun, spoon slaw over the top, place onions on top and drizzle with BBQ sauce. Serve.