Technology often yields ridiculous conveniences, like being able to turn on your computer from miles away without pushing the power button. Wake-on-LAN has been around for a while, so let’s see how it works and how we can enable it.
It basically allows a system that is "off" to be powered up when a packet is sent to the NIC. It is used more heavily in the IT Professional world as its useful for updating and troubleshooting remotely.
That would be the best option I could think of. Now getting your app to be able to send the required packet is up to you. I think you will have a lot of research to do and a lot of trial and error.