Hello,
Right now there is no support for adding additional key bindings in the EyeX SDK. The best way to accomplish this is to use the Gaze-aware behavior to understand which object the user is looking at, then hook up the keys yourself to perform different actions on the looked-at object.
If you are using Unity, the GetKey or GetButton functions are useful.
https://docs.unity3d.com/Documentation/ScriptReference/Input.GetKey.html
For other Windows development, check this article:
http://blogs.msdn.com/b/toub/archive/2006/05/03/589423.aspx