Have you read this, a lot of arch wiki is fairly generic and applies to many distros with modification... Just a matter of finding the alternate config files. Remembering of course that kali is gnome based, so you may wanna check that Gnome is not interferring/overriding the underlying x-settings. You may want to try this:
gsettings set org.gnome.settings-daemon.plugins.power active false
Is that systemd only? not sure, kali isn't systemd anywayz
Within your xorg X11 config file (/etc/X11/xorg.conf or somewhere not far away), the 0's == off
Option "blank time" "0"
Option "standby time" "0"
Option "suspend time" "0"
Option "off time" "0"
PS I don't think a dictionary attack is going to be your biggest worry, your 'site' isn't a word press site by any chance, if so you may wanna reconsider.
PPS If you're booting live then I think you need persistence for any of this, plus I'd consider the alternative pen-test tool set: Pentoo, it comes with PAX and GRSEC which are very handy if you wanna avoid being pwned yourself.
Edited by marcoose777, 13 July 2015 - 04:13 PM.