Toast the pita wedges: Preheat the oven 400°F then line a baking sheet with parchment paper. Brush both sides of the pita with olive oil and lightly sprinkle with salt. Stack two pitas on top of each other and use a sharp chef’s knife to slice into 8 small edges, as you would a pizza. Repeat with remaining pitas. Arrange the wedges evenly across the baking sheet and bake until they are light golden brown, for about 10 minutes, flipping halfway through.(Optional Step) Line a second baking sheet with parchment paper then spread chickpeas on top. Sprinkle with 2 teaspoons sumac then use your hands to roll the chickpeas until evenly coated. Bake in the oven for 10 minutes, stirring halfway through.Assemble the salad: In a medium bowl, combine the chickpeas, tomato, cucumber, green onions, parsley, olives, lemon juice, garlic, olive oil and salt. Toss, then taste test and add more salt, if needed. Set aside to marinate.Make the tahini sauce: In a small food processor or blender, combine the tahini, lemon juice, herbs, water, and salt. Blend until smooth, pausing to scrape down the sides as needed. Alternatively you can finely chop the herbs and whisk together the sauce in a liquid measuring cup. Add water as needed to thin. You should be able to drizzle it easily off the back of a spoon. Taste test and add more salt, as needed.Arrange the toasted pita wedges across a large serving plate, stir the salad once more then use a slotted spoon to scoop on top of the pita wedges, leaving the juices in the bowl behind. Drizzle with tahini sauce, finish with a sprinkle of chopped parsley, serve and enjoy!