To get it working:

1 Install the ADB Driver.

Follow the instructions on this page (make sure to restart the adb server when done) http://g-ecx.images-amazon.com/images/G/01/sdk/Connecting_your_Kindle_Fire_to_ADB.pdf

2 Install the APK.

First you need to download it directly, as we don't currently offer it in the Amazon store. You can get the current release from here: http://files.unity3d.com/ricardo/AndroidRemote.apk

Then follow the instructions for "Installing an Application" from here:

http://developer.android.com/guide/developing/tools/adb.html

3 When you connect the Kindle Fire exit the file transfer app. Then run the Android Remote app. Finally follow the instructions on the screen to use it.