I have never taken the skin off filet? how!
You can steam it with the skin on. When it's cooked the fish will easily separate from the skin.
If you steam the skin it's not a huge problem, the flesh will just flake off as you eat the finished product.
But if you want for a nicer presentation - to take the skin off slice between the fillet and the skin at the edge to get it started. Then hold your knife as flat to the cutting surface as possible and hold the skin that's now separated from the fillet taut. Slice between the skin and the fillet in a gentle sawing motion - gently pulling the skin taut will help you along.
You should be able to get the fillet away pretty cleanly - like anything it takes practice to become fully confident in the motion but you'll be fine! Good luck.
But, but why, why take the skin off anyway? Char is a fish similar to salmon and trout. Personally I would pan fry it with the skin on. Plate it up and if guests don't want to eat the skin fine. But it is perfectly edible.
I agree. I love crispy skin. But some don't.
I love crispy panfried fish skin but I don't love steamed fish skin.
The original question implies that they are steaming the fish.
Here is a video of how to skin a salmon fillet. It's the same technique for arctic char, although it takes a more delicate touch because the char skin is more delicate.