You can start Slicer with a script that hides all user interface elements that you don’t need. Maybe it could be then considered as a “simple DICOM viewer”. You can also run it in a docker container and make it available in a web browser (you then don’t even need to install anything).
@ihnorton How difficult would it be to make VNC access available for Slicer running using binder? Slicer could then work pretty well as a web-based DICOM viewer.