After a bit more searching I found my answer.
It's quite simple.
If you're already accustomed to connecting to your FIre TV over ADB, to push a file to a directory on the Fire TV, the command syntax is as follows:
adb push <local pc path to file> <destination path on fire tv>
For example, I wanted to push an XBMC repository zip to the /sdcard/download folder on my fire TV for ease of installation from within XBMC.
The zip archive is named "repositories_installer.zip"
and it exists in the following directory on my PC: C:\Android\FireTV\
To do so, my command was:
adb push C:\Android\FireTV\repositories_installer.zip /sdcard/Download