In a jar, combine 1 tablespoon Dijon mustard, 2 tablespoons apple cider vinegar, 2 tablespoons olive oil, 1 tablespoon water, 1 teaspoon sugar, and a pinch of salt and pepper. Shake vigorously for 30 seconds.

Peel and cube 2 pounds of waxy potatoes and place in a large pot covered with cold salted water. Bring to a simmer and cook for 4-5 minutes until fork-tender.

Transfer warm, drained potatoes to a bowl and pour the homemade French dressing over them, gently tossing to coat. Let sit for 2 hours.

In a small bowl, whisk together ½ cup mayonnaise, ¼ cup Greek yogurt, ½ teaspoon celery seeds (if using), and a pinch of salt and black pepper until smooth.

Add the creamy dressing to the cooled potatoes along with 1 finely diced cucumber, 1 cup sliced celery, ½ minced white onion, and most of the cooked bacon. Gently fold to combine.

Transfer to a serving dish and garnish with reserved crispy bacon. Serve immediately or chill for an hour to meld flavors.