I have my pi 2 running Kali 2.0.1 which is hooked to a 7in tft sun founder screen. The problem is that when unhook in micro USB port to power the pi is still running so in order to turn my pi off I have to unhook the hdmi and micro USB so shut my pi down.
I think it's all about the red light. You can issue the
sudo shutdown -h now command and when you see
system halted message it is safe to turn it off by removing USB. Taken from here. Not a bad idea is to add a button to the pi that will power on and off the device. Then add a shutdown script to turn the power led off
echo 0 >/sys/class/leds/led1/brightness. This will not tell you the exact turn off moment but will turn off the led.