Heat a grill or grill pan over medium-high heat. Drizzle the olive oil over the chicken breasts and sprinkle with oregano and salt and pepper to taste.
Grill for 4-5 minutes on each side or until cooked through.
Cut the chicken into 1 inch pieces
Combine the chicken, cucumber, tomatoes, chickpeas, red onion, kalamata olives, feta cheese and parsley in a large bowl.
Add the lemon juice and olive oil to the chicken mixture; season with salt and pepper to taste and toss gently until just combined.
Divide the chicken mixture evenly between the lettuce leaves and serve.
Notes
Make sure to use a preheated grill pan.
Drain your chickpeas well.
Be sure to cut all your ingredients into bite-sized pieces.
To check the doneness of your chicken you can use a meat thermometer. Stick it in the thickest part of the chicken, when it registers 165F your chicken is done.
Ideally use fresh lemon juice, a much better flavor than bottled.
You can swap the chicken for turkey or tofu - if you want a vegetarian option.