If you're developing those skins locally, running at a URL like http://dnndev.me/ you can make all the changes you want, without having to package/install the skins.
That is also the recommended approach for doing module development.
Here's a tutorial on setting up your local development environment:
http://www.christoc.com/Tutorials/All-Tutorials/aid/1
If you aren't doing local development, than you have to go through the hoops for packaging/deploying or uploading to the webserver via FTP/file system.