In order to use a USB-CEC Adapter with a HDMI Splitter you will need a CEC enabled Television to receive the signals, please note that most monitors don't have CEC. If you wish to use a Monitor please check the specifications of that model to see if it is CEC Compatible.
From there you will need 2 CEC Adaptors (one for each TV, a splitter won't be enough, you will need to insert the CEC's either after the splitter or direct from your graphics cards out).
You can then instruct your PC to turn on the monitors using zone trigger program and one of our drivers for the CEC (see the drivers bit here -