It should heal itself, and I wouldn't recommend putting any kind of sealant on the cut. If the cut is fairly large it might be a good idea to put some fungicide on it, to prevent disease from entering the wound. If the tree is in good health, however, the trees natural defense mechanism should protect it.

Your maple should be fine - I'd just leave it be. Bark trauma is not all that uncommon with J. maples, at least in my area. Squirrels are very fond of the tender bark - whether for eating or for nest building I've never figured out - and are often the source of bark stripping in early spring. Sometimes these torn strips are quite lengthy, but I've never encountered a J. maple that wasn't able to heal itself and recover nicely. Now if they remove the bark from all the way around the tree, you've got a problem.

Thanks, I've been worried about it, but since the tree seems healthy, I wasn't going to do anything, unless it looked necessary. I feel horribly guilty, though, I kept thinking all night long that I needed to go out & get the snow/ice off the tent, but I waited too long...

"Bark trauma" sounds like a veterinary complaint. Keep tree growing happily and it will fairly soon replace the lost bark.

Paul James in Gardening by the Yard on HGTV had some serious damage on a JM. Here's what he did....

Here is a link that might be useful: HGTV JM Repair

I don't know about the peat and plastic (link, above). For starters I wouldn't expect peat purchased nowadays to be sterile. Peat under clear plastic seems like a nice little environment for wood decay to get started.