To delete hiberfil.sys, just disable hibernation. Run CMD as admin, then at the command prompt, type “powercfg.exe -h off” without quotes, hit Enter, close the window.
To re-enable hibernation, use the command "powercfg.exe -h on" in an elevated command prompt.
To clear pagefile at shutdown, see this tutorial. It should work equally well for win7. It also addresses your security concerns.
Virtual Memory Paging File - Clear at Shutdown - Vista Forums