So this was a really interesting experience:
I launched the game so that I could check out all of the new stuff that was added, and I saw the new player skin system that was added. So I decided to mess around and see what kind of png file was required for changing the skin, but I couldn't find the default skin file anywhere in the game's folders on my PC, even when I searched the folders by putting *.png in the search function.
However, because the default skin texture loads when I launch Cosmic Reach, I knew that the file had to be somewhere, so I poked around in the game's files to see if I could find a jar file that contains the game's assets, and I found it.
I made a copy of the jar file and put the copy on the desktop, then I extracted the files into a folder and looked around. I saw the assets txt file and opened it, then I searched for "skin" and found the line that points to the directory containing the default skin file.
I navigated to that folder and BINGO! I found the player_default_skin file and moved it to my desktop so that I can open it in GIMP and edit it whenever I want to make a new skin.
Now some of you may be wondering how I figured this out so quickly without any prior knowledge of Cosmic Reach's game file structure.
I used to mess around with Minecraft's game files ALL the time, so when I launched Cosmic Reach and saw that the default skin loaded even when there's no skin png file present in the game's folders, I knew that the game's assets had to be stored somewhere within a jar file.
And the funny part about all of this is that I launched the game so that I could check out all the new stuff that was added, but I was distracted by the fact that I had no way of changing the default skin since I had no skin template that I could edit.
Either way, I still had fun exploring the game's files and learning about them, it's a win-win for me!