You might want to check out GNU parallel (which is written in Perl :)

$ mkdir subdir
$ for f in {00..10}; do touch subdir/$f; done
$ for f in {a..z}; do mkdir subdir/$f; done
$ parallel --verbose rm -r ::: subdir/*
rm -r subdir/00
rm -r subdir/01
[elided...]
rm -r subdir/z
[download]

--verbose is just to show that it's doing what you think, but isn't necessary. I didn't test whether it's actually faster or not with parallel.