If you have not yet activated your scan (i.e. when visiting the scan link you see a page asking your for an email address to activate it), you can use the “Delete this build scan” link at the bottom of the page to delete it.
If it has been activated, you can delete it from the build scan by clicking the icon in the toolbar at the top. If you clicked the “Remember me” checkbox when activating the scan you can delete it immediately. Otherwise, a confirmation email will be sent to the email address that activated the scan with a link that can then be used to delete it. You cannot delete a build scan you did not activate.
If you have any problems with this process, please contact firstname.lastname@example.org.