How to use arduino to boot and load an android app?

I am wanting to use an uno or teensy to just boot up when powered and automatically load an android app.

Or use arduino to split to two monitors so one can be used as the main touch screen and the other is the display for the app

Any direction would be much appreciated. The project is trying to get Real Dash app to run standalone during key turn. It would be directly connected to the obd2 port for data. I am trying to stay away from using the phone or tablet and want it to work alone.

Thanks in advance

As far as I am aware you cannot run an Android app on an Arduino. What makes you think that it is possible ?

You can e.g. connect the Arduino by BT to your Android phone and tell it to run the app.

It isn't very clear what exactly you want to do. What does "split to two monitors" mean?

My experience with apps made with MIT App Inventor is that the app makes the BT connection with the Arduino and not the other way around. So you would have to have an app operating on the Android device monitoring for the presence of the BT on the Arduino device. I don't think the Arduino can use BT to tell the Android OS to start an app.