Slice potatoes in half. Place sliced potatoes into a gallon-size ziploc bag and the chicken breasts in a separate gallon-size ziploc bag.
Prepare the marinade for both bags. In a bowl, mix together the lemon juice, vinegar, olive oil, garlic, oregano, coriander salt and pepper. Whisk together well. Evenly distribute marinade into each bag. Slice half a lemon and place it into the bag with the chicken.
Place bags into the refrigerator and allow to marinate for at least 45 minutes.
Prepare tzaziki sauce: In a medium bowl, combine Greek yogurt, diced cucumber, lemon juice, dill garlic, salt & pepper. Stir well. Cover and place into the refrigerator (I think it gets better the longer it sits.)
When ready to cook the chicken and potatoes, preheat oven to 400f degrees. Place marinated chicken and potatoes onto a baking sheet.
Bake for about 25-30 minutes (until chicken reaches an internal temperature of 165f degrees.)
Optional: Place baking pan under the broiler for about 2-3 minutes to crisp up the potatoes then garnish with fresh parsley.