Wash unpeeled potatoes. Boil potatoes just until firmly tender. Remove from heat and run cool water over while peeling (they will continue to cook, so this step must be done right away). Have dressing mixed and pour over each layer of warm potatoes. Add hard-boiled egg, radish slices, green onion tops parsley, and chopped celery. Taste dressing before adding to potatoes; it should be tangy. A short-cut is to use bottled Marzetti’s Coleslaw dressing. Lightly mix all ingredients. Chill before serving.