Begin by placing quartered red potatoes in a large pot and filling it with cold water to cover them completely. Set the pot on the stove over high heat, bringing the water to a brisk boil. Once boiling, reduce the heat to medium-low and let the potatoes simmer for about 20-25 minutes, or until they are fork-tender but not mushy. Drain the potatoes in a colander and allow them to cool slightly before handling.

After draining, let the potatoes cool in the colander for a few minutes. To expedite the process, you can run them under cold water or spread them on a baking sheet in a single layer. It's essential that the potatoes are completely cooled before mixing them with the tzatziki sauce to prevent a soggy Tzatziki Potato Salad.

In a large mixing bowl, combine the Greek yogurt, sour cream, freshly squeezed lemon juice, white wine vinegar, chopped fresh dill, and minced garlic. Using a spatula, thoroughly mix all the ingredients until you achieve a smooth and creamy sauce. Taste the tzatziki sauce and adjust the seasoning, adding salt and pepper as necessary to enhance the flavors of your Tzatziki Potato Salad.

Take your English cucumber and shred it finely using a food processor or a box grater. After shredding, place the cucumber in a clean kitchen towel or several layers of paper towels. Press firmly to squeeze out excess moisture; this step is crucial for maintaining the integrity of your Tzatziki Potato Salad and preventing it from becoming watery.

Once the cucumbers are prepped, fold them gently into the tzatziki sauce until well incorporated. Then, add the cooled red potatoes to the mixture, carefully folding everything together. Be gentle during this step to avoid breaking the tender potatoes while ensuring they are evenly coated in the delicious tzatziki dressing.

Taste the Tzatziki Potato Salad and adjust the seasoning with additional salt and pepper if needed. This is a great opportunity to add any extra herbs or spices you may enjoy. Remember, the seasoning should enhance the fresh flavors without overpowering the zesty zing of the tzatziki sauce.

Once seasoned to your liking, you can serve the Tzatziki Potato Salad immediately for a fresh taste, or cover it and chill in the refrigerator for at least 30 minutes to allow the flavors to meld together beautifully. For added flair, consider garnishing with crumbled feta or fresh mint just before serving.