- Bring 8 cups of water to a boil in a large pot over medium heat. Add potatoes and boil for 30 minutes, or until fork tender. Drain and set aside.
- While potatoes boil, whisk together olive oil, mayonnaise, rice vinegar, mustard, garlic powder, and salt in a small mixing bowl. Transfer potatoes to a large mixing bowl. Drizzle with half of the dressing and stir to coat. Cover and refrigerate 1 hour to chill.
- Stir remaining dressing with potatoes and add celery, green onion, parsley and dill. Stir well. Refrigerate until serving.