A nice relaxing game of Solitaire is a perfect way to practice using the virtual touch screen. In fact, Solitaire was originally included with the Microsoft Windows operating system to help train users to use the mouse in a fun way. This implementation of solitaire was originally created by Mikko Vornanen, who made it open source, available for anyone to use for free. I have hosted it on my own website for convenience and security.
Lichess is a great place to play chess both against the computer and against people. I find chess to be a perfect game to show practical use of the Virtual Touch Screen. As the Virtual Touch Screen is imperfect, you may be at risk for a mouse slip, so beware.
Google earth is a virtual globe with super detailed satellite imagery. It is a pretty amazing product that works great on touch screens with flawless multitouch pan and zoom. With the Virtual Touch Screen, it feels even more like a real globe.
Territorial.IO is an addicting game of territorial expansion. The Virtual Touch Screen is typically not quite as good as a mouse for competitive gaming, but Territorial.IO has strong support for touch screens built in and works well with the Virtual Touch Screen. While the default gesture settings will work fine, you may want to use an advanced gesture profile that provides a single gesture to perform a double click to attack.
Tier Maker helps you visually compare all sorts of things by sorting them into lists. It has been an important tool in many content creator's belts for some time now. By synergizing with the Virtual Touch Screen, it is possible to bump up the produced content another level.