In a medium bowl, combine olive oil and lemon juice. Whisk until combined.
Add the garlic, cumin, paprika, turmeric, curry powder, cinnamon, red pepper, salt and black pepper and whisk again. Pour the marinade over the chicken making sure it evenly coat (careful it will stain your fingers). Refrigerate and marinate for at least 30 minutes, up to overnight.
Preheat an outdoor grill or indoor grill pan to medium-low heat.
Thread the chicken pieces among 4 wooden or metal skewers, discarding the marinade in the bowl.
Grill the chicken, turning the skewers occasionally, until golden brown and cooked through in the center, about 15 to 18 minutes.To make the salad:
For the salad: In a medium bowl, whisk together the oil and vinegar and season with salt and pepper. Add the cucumbers, cherry tomatoes, and red onion and toss to combine.
Divide the lettuce between 4 bowls, top with tomato salad, feta and grilled chicken. Serve with Tzaziki for dipping.