I work at a generation facility and worked at a chemical plant before this, that being said, I have never run across a specific tool for cutting liquid tite flex.

I have always used the "score, bend and snip" method. Just score the plastic withe a knife, then bend it til the metal flex separates, Cut it with your dykes and viola, your flex is ready to go. If you are careful about it you get a very nice end. (Note: you need to have a good pair of cutters. I have tried the Sears brands and they don't seem to do a very good job. The cutting edge is to steep.)

With a little practice you can actually cut it faster this way than with a saw. And it is easier on a ladder than a saw.

Now, mind you, this only works with the smaller sizes. Once you get over about 2" you have a very hard time bending the metal part enough for it to separate. Then a hacksaw and a vise (or other method to stabilize) is needed. I have had power saws grab the thin metal and mess it up pretty well.

And, lets face it, you get over 4" and you can't really call it "flexable" anymore anyway. [Linked Image]