If you're doing this regularly, a good alternative is to install on a separate partition and symlink it. Then to delete, you just quick format the partition.
echo Y | format Z: /FS:NTFS /X /Q
Also, on Windows 10 you can use Ubuntu bash and run rm -rf. I've read that it's faster, but haven't tested extensively.
Update: I did a quick test with 100,000 files and the 'del /f/s/q foldername > nul' approach was about 50% faster than 'rm -rf' on my machine.