The logo attached to this project is the new one where you will have to apply the color changes to the PSD version.
For the front, I think if you could create some illustration of a Ninja preparing for battle or a Samurai's head and eyes.
Either way the illustration should be able to represent in some portion our logo where you can see the dots stand for the eyes and the big thing on the top representing a hat.
For the back, I think you could put the logo on it perhaps although I'm not too sure. I think saying in big words "NINJA" would look cool for our staff to wear around but the logo I think should be somewhere on the shirt whether be front or back.