Wrap potatoes in aluminum foil and bake at 400 degrees for approximately 45 minutes, or until tender.Let potatoes cool. When cool, cut potatoes in half lengthwise. Use a spoon to scoop out most of the soft center and place in bowl. Set aside.
Brush the potato skin halves lightly with olive oil or spray with canola oil and place them flat side down on a baking sheet. Put the skins in the oven at 400 degrees and cook until hot and crunchy, approximately 10-15 minutes. Add cucumber, celery, tomato, mushrooms and 3/4 of the chives to the potatoes. Add olive oil, vinegar, salt and pepper. Toss well.
Pull the potato skins out of the oven. Fill each potato skin with the potato salad mixture. Top each with a dollop of sour cream, blue cheese crumbles, turkey bacon (if using), remaining chives and a grind of black pepper. Serve immediately.