- In a large bowl, whisk together all of the ingredients. Season with salt and pepper.
- With the rack in the middle position, preheat the oven to 400°F (200°C).
- On a non-stick sheet pan, toss the chicken with two tablespoons of the dressing. Bake for 15 minutes. Set the remaining dressing aside.
- Remove the sheet pan from the oven. Arrange the tomatoes, olives and onion (see note) around the chicken. Bake for another 5 minutes or until the chicken is cooked through. Let cool for 5 minutes.
- On a work surface, thinly slice the chicken and return to the sheet pan. Adjust the seasoning. Sprinkle with the cheese and parsley. Add the cucumbers and lettuce to the bowl of dressing. Mix well.
- Serve the salad in bowls. Top with the chicken mixture.
Note: By adding the onion at this stage, it loses its strong raw onion taste while staying crisp. If desired, you can cook the onion longer by adding it at the same time as the chicken.