Suppose 'target\' contains a bunch of paths that are too long for Windows'
puny little brain. To delete it:

mkdir empty
robocopy /mir empty target

robocopy will now purge all the contents of 'target' in its effort to make its
contents a mirror of the empty folder.

Now, if only the standard Windows APIs supported whatever magic robocopy uses
for this...


Addendum:

rm -rf in cygwin also works