How to Make It
Combine chicken, cucumber, tomato, olives, and onion in a medium bowl.
Whisk together parsley, oregano, salt, pepper, vinegar, mustard, and honey in a small bowl. Slowly whisk in oil in a steady stream until blended. Toss chicken mixture with 1/2 cup of the dressing.
Place 2 romaine lettuce heart halves on each of 4 plates, and top each evenly with chicken mixture. Drizzle plates evenly with remaining 1/2 cup dressing, and sprinkle with crumbled feta.