Place quartered baby red potatoes in a large pot and cover with cold water. Bring to a boil and reduce to simmer for 20-25 minutes. Drain and cool completely.

In a mixing bowl, combine Greek yogurt, sour cream, lemon juice, white wine vinegar, dill, and minced garlic. Mix until smooth to create the tzatziki dressing.

Shred the English cucumber and wrap in paper towels to squeeze out excess moisture.

Fold the shredded cucumber into the tzatziki mixture until evenly combined.

Add cooled potatoes to the tzatziki sauce and gently toss to coat.

Sprinkle with salt and pepper to taste, stirring gently.

Chill for at least an hour before serving. Garnish with feta and mint if desired.