To make tzatziki, combine yogurt, cucumber, mint, garlic, lemon rind, lemon juice, olive oil, vinegar, salt and pepper. Chill for at least 30 minutes before serving.
To make cucumber salad, combine 1/2 small cucumber, tomatoes, red onion, and feta cheese. In a separate bowl, make vinaigrette by combining olive oil, vinegar and salt and pepper. Pour over cucumber mixture and mix to combine.