Hi, Anton -- BadgeKit is in maintenance mode and has no active development.Though it is open source, it is not being actively maintained, so discussions of issues and pull requests on its GitHub repos may not be resolved.
You can send a DELETE request to /systems/:slug/badges/:slug
Deletion may not be fully implemented in the openbadges-badgekit user interface. See more on how to build your own
authorization tech to authenticate requests.
If you find BadgeKit does not fully serve your needs, there are a number of
other platforms and solutions available. As far as other open source issuer software goes, there is also
Badgr (a project I work on at Concentric Sky)
Cheers,
Nate Otto
Director of Technology, Badge Alliance