To run at startup try putting the relevant command in ~/.config/lxsession/LXDE-pi/autostart
This works fine (@xastir), but just starts displayed on desktop 1. How can I get it to start on desktop 4 (or other)? Something like "@4xastir" ? Or let's say you name all your virtual-desktops (VDs). If you want several apps to start in a given named desktop, could it be something like:"@<VDname>.<app-cmd>"?
I'm reasonably experienced in Linux (Mandrake/Mandriva, Kubuntu), but this is beyond my 'paygrade'