I don't think I paid sales tax for all of the lease payments. What do I do?
The process will be the same as if you hadn't paid any sales tax at all. You'll have to provide DMV with your lease agreement and fill out a Statement of Transaction at NY State Department of Tax and Finance. The sales tax for any existing lease payments you have will be paid to DMV.
Can this be done online?
No, you will need to do this in person at a DMV office.