Sure, using an iPad as a second Mac display is old hat, and yes, Air Display ($9.99) is the ultimate tool for connecting your iPad to your Mac for that. But did you know that this app can also be used to interface with your Mac by using your iPad as a touchscreen? Here’s how:

1. Install Air Display on iPad and Mac

To connect to your iPad, select it from the Air Display menu item.

After downloading and installing the necessary components for Air Display on both devices, ensure that your iPad and Mac are connected to the same network, then launch the application on your iPad. Click the Air Display menu bar icon on your Mac and select your iPad from the available devices. Your iPad will now be configured as an Mac extra display, and its screen should appear on your iPad. If not, check your Displays Preferences.

2. Get to Touching

It may look like a Mac, but it’s a Mac-iPad hybrid, and it’ll play Flash content.

After everything’s set up, you can control your Mac using one finger as a single click and two fingers to scroll through web pages or other long documents. This especially works great with applications like the calculator on the Mac, a painting app, or even GarageBand. Unfortunately, Air Display won’t give you the fancy Multi-Touch gesture support that TouchPad does.