In a mixing bowl, combine olive oil, minced garlic, smoked paprika, dried oregano, cumin, salt, cayenne pepper, black pepper, lemon juice, and lemon zest. Whisk until well blended. Add the chicken thighs, ensuring they are coated in the marinade. Cover and refrigerate for at least 2 hours.

Preheat the grill to medium-high heat, aiming for about 400°F.

Place the marinated chicken thighs on the grill. Grill for 5 to 6 minutes on each side or until the internal temperature reaches 165°F.

Chop the cucumbers and finely mince the red onion in a bowl. In another bowl, whisk Greek yogurt, lemon juice, minced garlic, dill, salt, and black pepper. Pour over the cucumber and onion mixture and toss gently.

Remove the chicken from the grill, let it rest, then arrange on a platter and top with the cucumber salad. Serve immediately.