Bring a large saucepan of salted water to a boil. Add the potatoes and cook over high heat until tender, about 9 minutes. Drain, gently shaking out the excess water. Spread the potatoes on a baking sheet in a single layer and freeze for about 10 minutes, just until no longer warm.
Meanwhile, in a large bowl, whisk the yogurt with the mayonnaise until smooth. Add the cucumbers, garlic, mint and dill. Fold in the potatoes, season with salt and pepper and serve.
Cook's Note: Additions - Red onion, Kalamata olives or feta cheese.