Hi Alex,
WireframeSketcher always opens with the default workspace, however there is a "-data" command line option that you can use to force a different workspace location. See this article in our support section for more details on that:
https://wireframesketcher.com/support/faq/best-practices-for-organizing-projects.html
You can then create a custom shortcut that uses "-data" parameter with your workspace.
Let me know if this helps.