The other day I was need an app I could use to turn my tablet into an extra display. I also needed it to use the touch feature as the mouse input. After some searching and testing I landed on iDisplay. It will work with both your Apple products and your Android devices.
The application is easy to install and configure. You download the mobile app to your phone or tablet and the desktop app to your computer. After this you only have to launch the desktop app and voila you have a secondary monitor with touch input and sound as well. As long as you have both devices hooked to the same network, wired or wireless, it just works. You can move windows across any or all displays and it just works seamlessly.
You can find the download links for both iTunes & Google Play below and the program will set you back $4.99 on either platform.
https://play.google.com/store/apps/details?id=com.idisplay.virtualscreen – Google Play Store
http://www.getidisplay.com/ – Developers Site