You can not delete a user's history since it is a security issue. Just like pop up windows and cross browser scripting. If we enable it, it would be ugly.
What you can do with your site is try using the replace() method of the window object when you are using links and that will replace the current page in the history. Now if you are doing post backs it is not going to fly that well.
A site should be designed around the browser and not the other way around.