You can disable autolinks completely by unchecking all message types in AdminCP > Settings > Options > VaultWiki: General Settings > Enable Auto-Links.
Auto-links don't exist physically and cannot be "deleted". If they were included in your post cache, then you will have to rebuild the post cache (AdminCP > Maintenance > Update Counters > Rebuild Post Cache). Some large forums can't do this; they will have to wait for the cached posts to expire.