Such questions are important for us because they indicate where to improve our documentation.
The easiest way to achieve the desired result is to set the Title parameter of the GridCommandButton, and then pass it to the TargetSelector of your Tooltip. The described approach is showcased in the attached sample project.
I hope this helps. If you have any other questions, don't hesitate to contact us again.
Thanks Hristian... I guess I could have just tried the obvious but when I started to type "Title" it didn't show up as an option in the intellisense menu so I just assumed it wasn't a valid parameter.