As of now, it is not possible to tune the CapSense component using the CapSense Tuner over UART as communication is only one way.
You can, however, write firmware to change the parameters using the CapSense_GetParam and CapSense_SetParam APIs. Please refer to the datasheet of the CapSense component for details on how to use these APIs.
Please do let us know if this resolves your problem.
Thanks and regards