Is there any way to switch tabs using command+number? This feature is available in Atom, Code, and many other IDEs,
Unfortunately WebStorm does not have such functionality.
https://youtrack.jetbrains.com/issue/IDEA-68324 -- watch this ticket (star/vote/comment) to get notified on any progress.
At the same time -- try GoToTabs plugin -- it can do that.
You will have to add keyboard shortcuts yourself: to prevent any possible conflicts with already assigned commands, those actions do not have any shortcuts assigned.