In a large bowl, whisk together olive oil, ground cumin, paprika, turmeric, cinnamon, black pepper, salt, ground coriander, minced garlic, and lemon juice until well combined. Add the chicken thighs, ensuring they are evenly coated in the marinade. Cover the bowl with plastic wrap and refrigerate for at least 1 hour, allowing the flavors to infuse; for optimal taste, aim for 8 hours.

While the chicken marinates, preheat your grill pan or oven to medium-high heat (about 425°F). If using a grill pan, lightly coat it with olive oil. If roasting, line a baking sheet with parchment paper.

Once the grill pan or oven is preheated, place the marinated chicken thighs on the surface, ensuring they are not overcrowded. Cook for 5-6 minutes per side on the grill. If using the oven, roast for 25-30 minutes, flipping halfway through.

Remove the chicken from the heat and let it rest for 5 minutes, tenting it with aluminum foil. After resting, slice the chicken thighs into thin strips.

In a medium bowl, combine the plain Greek yogurt, mayonnaise, finely grated garlic, lemon juice, and salt. Mix until smooth and creamy. Cover and refrigerate the garlic sauce.

To serve, place the sliced chicken in warm pita bread, on a bed of rice, or atop a salad. Drizzle generously with the garlic sauce and add toppings such as cucumbers and tomatoes.