We think these actually look really healthy! We aren't sure what caused the white markings or if it is anything abnormal. 

The darker spots could be some cucumber beetle feeding which is very common as well. This doesn't make them inedible. If you are turned off to it though, you could just peel them. 

Do the leaves and overall health of the plant look ok? Its been hot and dry mostly so all vegetables are dealing with heat wave and drought symptoms even if you have been regular and diligent with watering needs. 

Emily