In a pot of salted water, boil potatoes until soft. Drain potatoes and transfer to a bowl. Add celery, onions, relish, bell peppers, mayonnaise, mustard, paprika, salt, and pepper and mix well.
Serve warm or cover with a folded paper towel or fabric napkin and refrigerate until ready to serve. (The towel prevents the potato salad from becoming watery because of condensation that forms while cooling.)