Prep the Starch (The Crucial Step): Boil the potatoes whole until fork-tender. Drain and let cool on the counter for 30 minutes, then cut into bite-sized pieces. Refrigerate overnight (minimum 6 hours).
Combine Ingredients: In a large bowl, gently combine the chilled potatoes, celery, red onion, chickpeas, and olives.
Dress the Salad: In a separate small bowl, whisk all the dressing ingredients together until smooth.
Toss and Chill: Pour the dressing over the potato mixture and toss gently until everything is well coated. Stir in the fresh parsley. Return the salad to the refrigerator for at least 30 minutes to allow the flavors to blend before serving.