1) You would have to type the name of the session. In this case I believe it is much easier to run putty by yourself and select the session in putty's login window.

2) If you have stored session in Putty with the same name as current session in WinSCP, WinSCP calls "putty.exe -load session" for that session. I hope that this is what you ask for.

A nice feature would be to be able to call PuTTY with the name of a saved PuTTY session (putty.exe -load "my session"), so I wouldn't have to resize then window etc. every time again.