The documentation says:
If you later decide to build a skipped commit, you can override any skip tags by rerunning the build. If you are using workflows, go to the Workflows page of the CircleCI application and rerun the entire Workflow or rerun it from failed jobs.
However, from the job view the only Rerun option I have is to “Rerun job with SSH”. Similarly the workflow view has no rerun option. Normally, if a workflow had been run before I would see a drop down of three options “Rerun”, “Rerun failed jobs”, and “Rerun from beginning”. I would expect similar options for a workflow that was skipped.