In a small bowl combine all ingredients and mix well. Add dressing to potatoes, mix well until evenly coated, and store in the fridge for 30 minutes to chill before serving.
(Makes dressing for only about 2-3 servings)
The ingredients all complement each other well, as the Dijon mustard and cayenne pepper add the right amount of heat, the celery gives the salad some bite, and the mint adds a very subtle freshness. I also love the flavour that fresh lemon juice adds to the yogurt. Enjoy.