Pat the chicken thighs as dry as you can with paper towel and then lay them skin-side up on a large plate. Refrigerate uncovered overnight so that they get nice and dried out.
The next day, preheat your oven to 450 degrees. Place the pistachios on a small baking sheet and bake until lightly toasted and golden brown, about 5-10 minutes. Watch closely as they cook quickly. Once cooked, set aside and place your oven rack in the top third of the oven (should be the second placement from the top of the oven.)
Toss the cauliflower and onion with 1 1/2 Tbsp of the oil and spread on a large baking sheet, sprinkling with a pinch of sea salt.
Place the dried chicken thighs in a large bowl and mix with the Zahtar, making sure the thighs are coated on all sides. Sprinkle with salt. Nestle the thighs, skin-side up, among the vegetables, making sure to not crowd the vegetables.
Bake until the chicken skin begins to brown and crisp, about 20 minutes. While the chicken cooks, whisk together the tahini, lemon juice and remaining 2 tsp of oil until thick and well mixed.
After 20 minutes, baste the chicken which the juices from the pan and bake an additional 5 minutes. Then, divide the tahini mixture on top of each thigh and spread out with a spoon evenly. Bake another 5 minutes, until the tahini is lightly brown and the chicken reads at least 165 degrees when the temperature is taken near the bone (if it reads a higher temp, that is okay too!) Finally, broil 2-3 minutes to really crisp the skin.
Squeeze a little bit of fresh lemon juice over the whole pan and then divide the chicken between 4 plates. Then, toss the vegetables with the cilantro, mint and Dukkah and divide between the plates. Chop the pistachios and divide between the plates.