In a large mixing bowl, combine the cubed chicken, smoked paprika, dried oregano, garlic powder, onion powder, turmeric, salt, black pepper, and 2 tablespoons of olive oil. Mix well until the chicken is evenly coated. Allow it to marinate for at least 30 minutes, or up to overnight in the refrigerator for more intense flavor.
Preheat your oven to 425°F (220°C). This high temperature will help achieve perfectly roasted sweet potatoes and juicy chicken.
While the oven is preheating, slice the sweet potatoes into even rounds. Place them on the sheet pan and drizzle with the remaining 2 tablespoons of olive oil. Season with salt and pepper, tossing to coat evenly.
Spread the sweet potatoes in a single layer on the sheet pan and roast in the preheated oven for about 15 minutes, until they start to soften.
After 15 minutes, remove the sheet pan from the oven and add the marinated chicken on top of the sweet potatoes. Return the pan to the oven and roast for an additional 20-25 minutes, or until the chicken is cooked through and the sweet potatoes are tender and caramelized.
While the chicken and sweet potatoes are roasting, prepare the tzatziki sauce. In a mixing bowl, combine tahini, grated garlic, lemon juice, honey, and a pinch of salt. Whisk until smooth and creamy. You can add a bit of water to reach your desired consistency.
Once the chicken and sweet potatoes are done, remove the sheet pan from the oven. Top with sliced dill pickles, pepperoncini, pickled red onions, sun-dried tomatoes, mixed herbs, crumbled feta cheese, and sesame seeds. Drizzle generously with tzatziki sauce before serving.
