Over time, we expect that the Data Viewer will grow to become more tightly integrated with SuperLab. Assuming that this integration proceeds, then file associations will definitely receive greater attention. You have raised a very relevant issue.
As Hank mentioned in a CLI-related post in 2007, there are a limited number of command-line options “provided and used by the host API on which SuperLab is built.” Data Viewer (like SuperLab) is also built with that same aforementioned host API. I dug around a bit to see if by chance there was something built-in that would address your current questions about file associations.
I came up with one potentially helpful answer and a second, not-so-helpful answer. The “not-so-helpful” answer is that there do not appear to be any currently-available tricks to get a control-click system to work on the Mac.
The potentially helpful answer is that you CAN use the asterisk/star * file-globbing symbol to launch the Data Viewer with multiple files.
$ /Applications/Cedrus\ Data\ Viewer.app/Contents/MacOS/Cedrus\ Data\ Viewer ~/folder_with_data_files/* &
Just as we have said about the SuperLab command-line interface, the Data Viewer command-line options are also a “work in progress.” For someone with the impressive command-line chops that you have, Greg, the command-line experience of the Data Viewer is most certainly not up to par with most scripting utilities you likely know and love. This is to be expected, of course, because the main focus of the Data Viewer 2.0 was on its graphical features such as flagging and highlighting.
Thank you for raising the file-association suggestions. We definitely appreciate the feedback.