I definitely understand needing to delete photos from Photo Stream. I found an article that talks about deleting photos off of Photo Stream. This article will help you identify if you have the minimum system requirements to use the delete feature:
- iPhone, iPad, or iPod touch with iOS 5.1 or later
- Mac with OS X Lion v10.7.5 or later, and iPhoto 9.2.2, or Aperture 3.2.3 or later
Also, if you delete the photos from the Photo Stream section on your iOS devices and Aperture, the photos still remain in the Camera Roll or Library if they are also there. You can find the full article here:
I hope this helps!