Preheat griddle to medium heat. Fill a medium saucepan three-quarters full of water; bring to a boil. Add hot dogs, reduce heat to simmer, and cook until hot dogs are plump and heated through, about 6 minutes.
Using tongs, transfer hot dogs to griddle. Open buns and place interior-side down on griddle. Cook hot dogs and buns until lightly browned.
Serve hot dogs in buns with mustard, coleslaw, chili, and onions.