There has been a lot of talk around (Reddit) about Kali Linux 1.1 for the latest Raspberry Pi version 2. There were instructions around on how to build it yourself. If you want to download the official image from Offensive Security, get it here.
The image doesn't have raspi-config preinstalled. If you're not familiar, raspi-config is a configuration tool that makes it easy to expand your filesystem, overclock, activate a camera, set the hostname, and more.
To install raspi-config:
dpkg -i triggerhappy_0.3.4-2_armhf.deb
dpkg -i lua5.1_5.1.5-4+deb7u1_armhf.deb
dpkg -i raspi-config_20150131-1_all.deb
Once you've run raspi-config, expanded your filesystem and restarted, you may want to install more Kali packages as the image comes with very little preinstalled and it doesn't have the traditional Kali menu. Here's how to add Kali metapackages.
Update: I'm finding broken applications after an "apt-get install kali-linux-full". I ran "service metasploit start" and got an error "unknown service". Running "apt-get install metasploit" should fix that, even though metasploit was already in the Kali menu.