Wash and scrub 1 to 2 pounds of potatoes under cold water. Place in a pot, cover with cold water, and add salt. Boil, then simmer until fork-tender.

Whisk together olive oil, lemon juice, sumac, salt, and pepper in a bowl. Ensure the dressing is well-combined.

Drain the potatoes and let cool for 15 minutes, then chop into bite-sized cubes.

In a large bowl, combine potatoes, parsley, onion, cucumber, tomatoes, and olives. Fold the ingredients together.

Pour dressing over the salad and toss gently to coat, preserving the shape of the potatoes.

Taste and adjust seasoning. Let the salad rest for at least 30 minutes before serving.

Serve chilled as a side dish or part of a mezze platter.