Begin by boiling whole, unpeeled Yukon gold or red potatoes in a large pot of salted water for about 20 minutes, or until tender but firm. Drain and let cool slightly.

Carefully peel the cooled potatoes and cut them into bite-sized cubes. Place the cubed potatoes in a large mixing bowl.

Add finely diced red onion, chopped parsley, pickles, black olives, capers, and sun-dried tomatoes. Gently fold together.

Drizzle olive oil and balsamic vinegar over the mixture. Sprinkle salt, chili flakes, and sumac. Mix gently to combine.

Toss the salad gently to combine all ingredients, maintaining the structure of the potatoes.

Taste and adjust seasoning before serving. Let sit for about 10 minutes to allow flavors to meld.