In a large bowl, combine tahini, za’atar, red wine vinegar, fresh lemon juice, minced garlic, salt, and pepper. Whisk until all ingredients are well incorporated and smooth.

Set aside a couple of tablespoons of the marinade for later use. Coat the boneless skinless chicken thighs thoroughly in the remaining marinade. Cover and refrigerate for at least 1 hour, though overnight gives the best flavor.

Preheat your oven to 400°F (200°C) to ensure it's hot and ready for the chicken to roast to perfection.

Place the marinated chicken thighs on a parchment-lined baking sheet. Roast in the oven for 25-30 minutes, or until the chicken is golden brown and reaches an internal temperature of 165°F (74°C).

Drizzle the reserved marinade over the baked chicken. Garnish with fresh parsley and serve with lemon wedges for a refreshing touch.