I have come across some of these too and always end up cussing. The normal corbin hose clamp pliers don't work because when you try to squeeze the clamp, the loops get in the way of the pliers closing. And they often need to spread further apart than flush to remove.
I have never seen a dedicated tool.
I decided to play around with the idea a little and found that of all things, wire rope cutters work surprisingly well. The bypass shear cutting edges allows the clamp to spread past itself unhindered, and the curvature keeps the loops from slipping off and locked in. The sharp hook point of the jaws will also dig and grab the loops when the clamp is partially buried in hose. These cutters typically open pretty wide and should accommodate a pretty good range of sizes.
One thing to note is that this only works with the loops in the orientation pictured. If they are like the OP's pic, they would need to be flipped around, but that's not a deal breaker and can be done before removal.
I have a couple different pairs of these wire rope cutters and my generic imports have a metal loop to keep them closed when not being used. But in this case it also works to keep the clamp held open.
