Wash, peal, and cut the white potatoes into 3/4 inch cubes. Wash and cut the redskin potatoes into 3/4 inch cubes, but do not peal!
Boil the white skin potatoes until a fork easily breaks them in half.
Place the redskin potatoes on a baking sheet, lightly spray with oil, and roast in a 400 F oven for about 30 minutes or just until they begin to turn a golden brown. Depending on your oven, you may need to stir them multiple times to prevent burning!
Prepare coating by mixing the mayonnaise, pimientos, shallots, celery, vinegar, apple juice, and mustard in a large bowl. Set aside in refrigerator.
When potatoes are cool, dump them into the large bowl, add cooked bacon, and mix until well coated. Refrigerate until serving.