Place whole small potatoes in a big pot of salted water that covers them by about 1 inch. Bring to a boil.
Turn heat to medium-low and simmer for about 20 minutes, until tender all the way through.
Strain potatoes, reserving about 1 cup of cooking liquid. Place potatoes in a big mixing bowl.
Using two knives, cut up the potatoes into big chunks using a crisscross cutting motion.
Add mayonnaise, mustard, chopped pickles and onions to the potatoes. Mix well, but softly, trying not to break the potatoes up much more.
Add more mayonnaise or mustard as needed to create desired consistency. If consistency gets too thick, add back in a little of the cooking liquid to loosen it up.
Fold in bacon crumbles. Season to taste with salt and pepper. Eat warm, cold, or somewhere in between.