xubuntu – How to make an app fullscreen (not maximize) in xfce with a touchscreen gesture?

I am running Xubuntu in a touchscreen tablet without a keyboard. While I can press F11 with an on-screen keyboard to make an app fullscreen, that is cumbersome.

Is there any way to set up a touchscreen guesture to go in and out of fullscreen mode for the app which is currently focused?

Is there any other simple way to make the app fullscreen, such as adding a fullscreen button to the titlebar (in that case how shall I get out)?

Note: I am looking for how to fullscreen, not maximize.