1. To marinate chicken: in a medium bowl mix plain Greek yogurt, zest from one lemon, juice of one lemon, salt, pepper, oregano. Add the chicken breast and turn to coat, cover and refrigerate for 2 hours.
2. When the chicken is ready, preheat the oven to 375 F.
3. Bake chicken covered in a large baking dish for 20 minutes, then bake uncovered for another 10 -15 minutes until meat is tender.
4. Chop tomatoes, cucumbers, green bell pepper, red onion into large chunks.
2. Cut feta cheese into small cubes.
3. In a medium bowl, combine all the ingredients, drizzle with olive oil, salt, pepper and dry oregano. Mix well.
4. Serve the salad with chicken. Enjoy!