To read the ESC command, go on APM Planner and look at channel output, I believe is something like SERVO_RAW_OUTPUT.
What you ask for is the motor/propeller data sheet, and you should ask your supplier for your specific model. Those data are not easily accessible, the best way is to get your own motor test bench Because the combinations of motors, propeller and esc can vary the graph a lot.
Some motor manufacturer provide sparse information about their performances, like here http://www.rctigermotor.com/html/2013/Professional_0912/43.html
You could simply fit it to a second order system for now with those data points, choose the correct propeller size and comparable motor for your estimation. But Erle is not the right one to ask for that here. I highly doubt they developed the propellers themselves