"Skirting" is what you see in trailer parks - covering the perimeter around the trailer (where your brick is sitting on the photo).
What you need is a piece of aluminum "siding" for your particular model. Most dealers will be able to get it. They might send you a piece with straight ends in 6" increments, so you'll have to cut it to size. Specify the length and model year. Or - better yet - come in person with a sample, to make sure that the width and color are what you need. Cut out a vertical strip next to the damage and put a duct tape for now, you'll throw it to garbage anyway.
Just replaced a 5 ft long piece of corrugated aluminum on my trailer.