At this size, these would be great for a buffet or picnic or as a way to serve potato salad in a more elegant way than the usual giant bowl. It would also be great for portion control.
If you want to make one-bite potatoes, the concept is the same. Just buy smaller potatoes. and chop everything a little smaller so it fits the scale of the tiny potatoes.
And, obviously, you'll need less of everything else per potato.
4 hard boiled eggs, peeled and chopped
2 tablespoons sweet pickle relish
2 teaspoons yellow mustard
1 teaspoon horseradish
1/4 - 1/2 cup mayonnaise
salt and pepper, to taste
paprika, for garnish
Slice the potatoes in half horizontally and use a melon baller or spoon to scoop out the inside of the potato, leaving about 1/2 inch all around to make a shell that can be filled. Try to leave relatively large chunks of potato as you remove them.
Put those scooped-out potato pieces in a bowl. Add the eggs, relish, mustard, horseradish, and half of the mustard. Add salt and pepper, to taste. Add more mayonnaise, if you need it - you want the mixture to hold together, but not be loose.
Using a disher (easier) or a spoon (messier), pile the potato salad into the scooped out potatoes. Garnish with a sprinkle of paprika.