Use Raspberry and Arduino IDE to programm ESP8266
Have you tried installing Python for Windows? 

http://docs.python-guide.org/en/latest/starting/install/win/

In theory it should work and you should be able to run esptool.py on a Windows command line like you do on your Pi (provided that your usb to serial in recongnized by Windows).

If esptool.py fails to run under Python for Windows I would first suggest to open a ticket with the esptool maintainer and then try under a cygwin environement (https://www.cygwin.com).