For the best flavor, use high-quality feta cheese and Kalamata olives. Feel free to add other toppings such as grilled chicken or gyro meat for a heartier meal. If you prefer a spicier kick, add a pinch of red pepper flakes or a drizzle of hot sauce. To make your own tzatziki sauce, combine Greek yogurt, grated cucumber, minced garlic, lemon juice, olive oil, and dill.