Place unpeeled Yukon gold or red potatoes in a large pot of salted water and bring to a vigorous boil. Cook for about 20 minutes until tender. Drain and set aside to cool.

Once cool, peel the potatoes and chop them into bite-sized cubes. Set aside in a large mixing bowl.

Add the sliced red onion, chopped parsley, diced dill pickles, black olives, capers, and chopped sun-dried tomatoes to the bowl. Gently toss to combine.

Drizzle olive oil and balsamic vinegar over the potato mixture. Gently fold to coat without mashing the potatoes.

Sprinkle salt, chili flakes, and sumac on top. Toss gently to ensure every cube is coated.

Taste and adjust seasoning with extra salt or sumac. Let the salad sit for at least 30 minutes before serving for flavors to meld.