Take the cooled potatoes and cut into quarters. Scoop out and discard the potato flesh (or use for another recipe). Transfer the skins to a bowl and spray with a little oil.
Cook the skins cut-side down on the barbecue for 2 minutes, turn and carefully sprinkle a little cheese on to each skin. Cook for a further 2 minutes until the cheese is melted.
Meanwhile, make the dip. Combine the ingredients in a bowl and season to taste. Serve the skins with the dipping sauce.