How many days after volar ganglion cyst surgery can I go back to work?

It depend. What can a work you do from few days (3) after the surgery to 6 weeks.
Depends. A lot depends on your work and how strenuous it is. If minimal activity, a few days. If heavy lifting is involved 1-2 weeks.
Depends on the job. Light office work the next day carpentry for example, may have to wait 2 weeks or so. Your surgeon is the best person to guide you.