Making the Tzatziki Sauce: Drain the yogurt for an hour in a strainer lined with cheese cloth. Combine strained yogurt with the rest of the Tzatziki Sauce ingredients. Mix ingredients together in a bowl.
Making the Tahini Sauce: Combine all the Tahini Sauce ingredients in a bowl. Mix and set aside.
Preparing the Falafels: Whisk water with the falafel mix until it becomes a thick batter consistency. Allow the falafel mix to sit for a half hour in the refrigerator and then add additional water to achieve the same thick batter consistency.
Heat the Evo grill to Medium and lightly oil the cook surface with olive oil. Spoon four-ounce portions of falafel mix onto the hot grill and brown on both sides. Place pitas on the grill to warm. Cut the cooked falafel into pieces and roll into a warm pita with diced tomatoes, cucumbers, red onion, lettuce, Tahini Sauce, and Tzatziki Sauce. Enjoy!
