You're right. The sensors board includes level shifters and pin header for SPI but these are not available via grove connectors and the getting started kit does not include an SPI devices.
You should be able to use the sensors board together with an SPI peripheral board (eBay is good for finding these).
Alternatively the http://www.96boards.org/product/linker-mezzanine-starter-kit/ has a MCP3004 ADC soldered onto the board itself. This device is hooked up via SPI.