Begin by placing the quartered baby red potatoes in a large pot and covering them with cold water. Bring the pot to a rolling boil over medium-high heat, then reduce the heat to a simmer. Cook for 20-25 minutes until the potatoes are fork-tender but not mushy, then drain them in a colander.

After draining, transfer the potatoes to a strainer and let them cool completely. To expedite the cooling process, you can rinse the potatoes under cold running water.

In a large mixing bowl, combine the Greek yogurt, sour cream, fresh lemon juice, and white wine vinegar. Add the chopped fresh dill and minced garlic, stirring everything together until smooth and well mixed.

Next, shred the English cucumber using a food processor or grater until finely shredded. Place the shredded cucumber between paper towels and gently press to remove excess water.

Fold the drained cucumber into the tzatziki sauce, mixing well. Then, gently add the cooled potatoes and carefully fold them into the mixture until each piece is coated.

Once combined, taste the Tzatziki Potato Salad and add salt and pepper to your liking. Serve it immediately at room temperature or refrigerate it for at least 30 minutes before serving.