Tzatziki is a Greek yogurt sauce made with cucumber and garlic. Tzatziki is most commonly know as the sauce on Gyros but is great for lots of other things. It's a wonderful appetizer with grilled pita and goes well with roasted or grilled chicken or lamb.
Start by washing the cucumber and grating it skin and all. You can use a food processor or a hand grater with large holes. Squeeze the grated cucumber with your hands to drain off the excess water.
Mix the cucumber, yogurt, garlic powder, olive oil, and lemon juice together. Serve cold.