Example of GoToMyPC. This application includes Alt, Ctrl, Tab and F1-F12, among others. Using these keys, you can use shortcuts like Ctrl + C to Copy, and you can send Ctrl-Alt-Del by tapping those keys on the mobile keyboard toolbar one after the other (not simultaneously).
It seems it was mainly designed to be used for personal computers. How can it be used more effectively on Android or iOS devices?
According to the FAQ you can even use it on 3G and 4g:
Q: Can I use GoToMyPC mobile apps on a 3G or 4G network?
Yes, GoToMyPC mobile apps work on 3G, 4G and Wi-Fi networks and automatically switch to a better network without disconnecting the session. The apps are also optimized to handle intermittent network connectivity so your session is not interrupted if you’re on a spotty 3G network.