Peel Potatoes and boil for 30 minutes or until just soft do not over cook. Use fork to test doness every couple minutes toward the end. They should be firm but not soft
Cool potatoes for about 15 minutes then halve and slice in 1/3" slices
Pour italian dressing over and toss thouroughly refirgerate for 2 hours
Hard boil the eggs ( put eggs in cold water then bring to full boil. Remove from heat cover and 13 minutes later remove) Separate yolks from whites.
Chops whites and puree yolks with fork
Mix cucumbers, green onions, celery and egg whites
Mix mayo, mustard, celery seed, sour cream, pepper, horseradish, and egg yolks.
Add mayo mixture and cucumber mixture to potatoes stir to thouroughly encorporate
Cover and refrigerate no less than 2 hours