Hi Hayden,
You can retrieve the dataset of a report element (in this case a VTable) using the following URL:
GET .../raylight/v1/documents/<docId>/reports/<reportId>/elements/<elementId>/dataset
the documentation can be found at:SAP BusinessObjects Business Intelligence platform 4.1 – SAP Help Portal Page
Look for the guide: "SAP BusinessObjects RESTful Web Service SDK User Guide for Web Intelligence and the BI Semantic Layer" and go to the section on report elements. There is a sample response for a vTable element that should meet your needs.
Dan