jwm doesn't seem to be intrusive.
I have never run kiosk mode
if your intention is to have no keyboard can I suggest for jwm you have a peep at
~/.jwm-tray
eg change FF button if you need to from
<TrayButton label="FF">exec:firefox-perf</TrayButton>
probably remove all buttons except FF and x and maybe add if you like it
<TrayButton label="Keyboard">exec:xvkbd</TrayButton>
I have a mouse rather than a touch screen. Suggest you play with the height of the tray currently set at 20.
Suggest you move the X (exittc) button next to the FF button?