Mix together the olive oil, garlic, oregano, salt and 2 tbsp lemon juice in a bowl.
Put the chicken pieces and marinade in a ziploc bag, squeeze out extra air, seal and mix thoroughly in bag. Place in fridge for 2 hours.
For the rice, cook rice in a pot per instructions but instead of water, use stock, 1 tbsp lemon juice, garlic powder and butter/margarine. Season with paprika and parsley.
Grill chicken pieces 2 minutes per side til brown, in batches if necessary. About 20 minutes total
Brush a non stick skillet with olive oil. Fry pitas 2 minutes per side on medium, cover to loosen up.
Assemble pitas- scoop on tzatziki, then lettuce, then onion slices, then tomato slices then chicken. Top with hot sauce if desired.