It's in the initial install download. There are menus where you can choose the tire size, etc, and the speed limiter is one of the choices. You just need to re-download your tuner to your truck. It's all in the manual if you need a reference while you're doing it. Also, if you haven't updated your Mini Maxx to the new version and firmware, now might be a good time to do it.
And you can't remove the limiter, but you can set it as high as 200MPH, which essentially removes it. I think the limit is initially set at 95 though. Do you often find yourself needing to exceed that?