This raita is a fresh dip to serve with toasted pita or chips. It can also be used as a cooling accompaniment that tempers the heat of a spicy curry.
Slice the cucumber in half. Use a spoon to scrape out the seeds, then grate it onto paper towels. Squeeze the cucumber in the paper towels to remove the excess moisture, then set aside.
In a bowl, stir together the yogurt, cumin, coriander, cayenne, lemon juice, salt and pepper. Add the cucumber and stir to combine, then stir in the mint. Taste and adjust the seasoning as you desire.
Cover and refrigerate for a couple of hours to allow the flavors to combine. Serve as a dip with pita wedges.