First of all, I needed to find the email linking to the download. This wasn't in my spam folder as the website suggested, but in "Promos".
After getting the ISO, this sums it up:
http://www.cincomsmalltalk.com/main/questions/question/how-do-i-install-cincom-smalltalk-on-linux/
Basically:
- Make sure that the appropriate VM is selected during installation and
- Go through the launcher menu System → Load Parcels Named... and load "Xft" and "Xft-Integration". It has to be done through the launcher like this specifically because I found some other way of loading parcels and I got some message about how the format was invalid.
- Save the image and restart.
What you will see is an enormous improvement over the jagged eyesore that is core font rendering in the X Window System.