Heat a large skillet over medium-high heat. Add the cumin and coriander to the hot skillet and stir to toast until they become aromatic, about 30 seconds. Add the oil and turkey, breaking the meat up with a wooden spoon into small crumbles. Sprinkle with 1 teaspoon salt and toss it so the turkey is coated in oil and spices. Cook, stirring occasionally, until the turkey starts to brown, about 2 minutes. Grate the garlic cloves on a rasp grater into the skillet. Stir it into the turkey and cook until turkey is browned and fully cooked, 4 to 5 minutes more. Stir in the oregano, some lemon zest and half the lemon juice, scraping up browned bits left in the skillet. Remove from the heat and set aside.
For the kids: Put 2 naan on a baking sheet. Spoon 2 tablespoons pizza sauce on each. Add a little bit of turkey and the mozzarella. Bake until the cheese is bubbling and the crust is golden brown, about 10 minutes.
For the adults: Mix the tahini with the harissa, remaining lemon juice, a pinch of salt and 2 tablespoons water if desired (see Cook's Note). Spread the tahini sauce on one side of the remaining pieces of naan. Sprinkle turkey on top of the sauce. Bake until the crust is toasted, 10 to 15 minutes. Layer on feta, cucumbers, olives, red onion, parsley and mint leaves. Sprinkle with some lemon zest and spritz with a little lemon juice. Drizzle with additional tahini sauce if desired. Serve hot or at room temperature.
You may or may not need water, depending on the consistency of your tahini. See what works for you!
These naan are so big that my kids never finish them for dinner. I zip them in a bag and send pizzas to school with them for lunch.