Edit this file
sudo nano /etc/xdg/lxsession/LXDE-pi/autostart
And add this:
@xset s off
@xset -dpms
@xset s noblank
@chromium-browser --kiosk http://google.com/ # load chromium after boot and open the website in full screen mode
Then reboot. Chromium should automatically launch in fullscreen mode after the desktop has loaded.
Note: The default file ( /etc/xdg/lxsession/LXDE-pi/autostart ) is the global autostart and is executed each time a user logs into the desktop. In case you want to use local autostart, use /home/pi/.config/lxsession/LXDE-pi/autostart
. Local autostart(s) are useful when you want to run different programs or configurations for each user.
You can also add this line if you want the mouse to disappear:
@unclutter -idle 0.1 -root
(requires sudo apt-get install unclutter
)