The access is "prevented" just by the weird name (...) which many tools don't support. You don't have to use Native API - you can use the ordinary Win32 API, but you need to use the \\?\ prefix with the path.
You can even use the usual command line tools, e.g.
Code:
mkdir \\?\C:\\Winmend~Folder~Hidden\...\cn
or
Code:
rmdir \\?\C:\\Winmend~Folder~Hidden\...\cn
Code:
rmdir \\?\C:\\Winmend~Folder~Hidden\...