For the dressing im using 1/2 fat olive oil based mayo by Hellman's with dijon mustard. Then again, those a personnal preference. If you have a different mayo or better yet, wanna make your own go for it!
I always see hot dog mustard in this salad but I think the spiciness of the dijon adds something more and allows you to keep the seasonnings fairly simple: salt and pepper with a handful of freshly chopped parsley.
Im also allowing you to change what kind of onions you wanna use. Play around with the ingredients, add cheese if you feel like it or even sweet corn! If you make this salad in advance, I suggest to add the bacon just before you serve. That way it will remain crispier than if it bathed in mayo over night ;)
1lb potatoes
2 ribs of celery
1/2 red bell pepper
1/4 red onion
a handful fresh parsley
1/4 cup mayo
2 tbsp dijon mustard
salt and pepper to taste

OPTIONNAL - Candied Bacon
3 slices of bacon
2 tbsp brown sugar
1tsp paprika