Is it possible to push a store app such as iheartradio into windows 10 iot or do I have to write my own?
I looked around but so far there are no examples on how to push an existing store app to iot.
As of now the Windows IoT Core is not managed, nor store apps can be deployed on the IoT core.
You can deploy an Appx that you have on to the IoT Core yourself. Note: Not everything that works on Windows Store will work on IoT Core; especially any Store APIs leveraged.
I have deployed a few XAML Apps across Windows 10 PC, Windows 10 mobile and IoT core. Let me know your requirement.