Here's how I solved this:
ln -s /dev/ttyUSB0 com5
That's all it required. My Windows app now gave me an option to use COM 5, and it worked right away.
In my research on this I did read that some people need to add a Wine registry key. I did not have to do this.
This is the common option that works with most applications:
Here are the resources I used for my solution:
Set up the serial port in Wine · One Transistor
wine - Symbolic Link Between USB and COM Port - Ask Ubuntu
Converting the /dev/ttyUSB to com port to use it with Wine in Linux - Super User