
Build a charcoal fire for direct grilling and preheat to 400 degrees Fahrenheit. Lightly oil the grates to prevent sticking.
Butterfly hot dogs by slicing them lengthwise without cutting all the way through. Open gently so they lay flat on the grill. Cook for about 2-3 minutes on each side, until charred in spots and hot throughout.
While the grill is heating and the hot dogs are cooking, grill the buns quickly over direct heat until lightly toasted - about 1 minute. Place one hot dog in each bun, and top with a quarter of the mustard, relish, onions, tomatoes, and one pickle spear. Add sport peppers, to taste, and sprinkle with celery salt. Repeat with remaining hot dogs and serve immediately.