In a large mixing bowl, combine Greek yogurt, olive oil, lemon juice, minced garlic, ground cumin, turmeric, smoked paprika, ground coriander, salt, and pepper. Add the boneless, skinless chicken thighs, ensuring each piece is well-coated with the marinade. Cover the bowl with plastic wrap and refrigerate for at least 2 hours, ideally overnight.

In a separate bowl, mix together Greek yogurt, grated cucumber, lemon juice, minced garlic, chopped dill or parsley, salt, and pepper. Stir until smooth and well-combined, then cover and chill it in the refrigerator until serving.

Preheat your grill or grill pan to medium-high heat, around 375°F to 400°F.

Remove the marinated chicken and thread the thighs onto skewers. Grill for about 4–5 minutes on each side, until nicely charred and cooked through.

Once grilled, let the chicken rest for a few minutes. Serve hot, drizzled with yogurt sauce.