Make the dressing: Whisk the mayonnaise, vinegar, mustard, poppy seeds, honey, 1/4 teaspoon salt, and pepper to taste in a bowl. Cover and refrigerate until ready to use.
Prepare the sandwiches: Preheat the broiler. Tear the hot dog buns in half lengthwise at the seam, then cut each side in half crosswise to make 8 pieces; flatten slightly with your hand. Arrange the bun pieces on a baking sheet and broil until golden, about 2 minutes per side.
Cook the bacon in a skillet over medium heat, turning, until crisp, 5 to 10 minutes. Drain on paper towels, then break each piece in half.
Split each hot dog lengthwise, about three-quarters of the way through, and open like a book. Melt the butter in a nonstick skillet over medium heat. Place the hot dogs cut-side down in the skillet; cook until browned and heated through, about 2 minutes per side. Cut each hot dog in half crosswise.
Sprinkle the tomatoes with celery salt. For each sandwich, spread 1 bun piece with some of the dressing and top with a piece of bacon, tomato, red onion, cucumber, lettuce and a hot dog; drizzle with more dressing and top with another bun piece. Repeat to make 2 more layers, ending with a bun piece. Secure the sandwich with a long skewer; top with a dill pickle slice and a pickled pepper.