Preheat oven to 400 F. Prepare a baking sheet, lightly brush with vegetable oil.
Cut potatoes into ½ inch pieces. Place potatoes in a bowl, add oil, sumac, salt and pepper. Toss potatoes, making sure they are evenly coated in oil and seasoning.
Roast potatoes for 25-30 minutes, flipping once, until golden and cooked through. Roast for additional 5-10 minutes, if potatoes appear undercooked.
Transfer to a bowl and let them cool for 20 minutes.
In a small bowl, whisk together oil, salt, lemon juice and paprika.
Set aside.
Place potatoes in a bowl.
Add sliced cucumbers and mint.
Pour dressing on top. Serve.
