SFTP File System allows you to use ssh to access files on a Linux or Windows computer. The neat thing about this app is it use the Files app in Chrome OS.
I am using LXDE on Linux Mint 17.1, and all I needed to do was install ssh server to get the SFTP app to work. I am just using this on my LAN so I just used the desktop's username and password, but if this was a public setup a public key would be a good idea.
What this app allowed me to do was access my home directory and my external hard drives on my Chromebook. This is on the beta channel and as you will see error messages popup, and I had to wait about 10 minutes after mounting for it to work, but overall I found the app did its job.