Seeing the menu on both displays? I don't know how much experience you have on Macs but I'll start by noting that OS X multiple display behavior, including location of the menu bar, changed in recent years. So...now in normal OS X behavior the menu bar is on every screen.
I'll tell you how to get it to show on one monitor, but not necessarily the same monitor all the time, and you'll change it back within 15 minutes as that setting completely ruins the use of two monitors for most folks.
System Preferences>Mission Control and uncheck "Displays have separate Spaces". You'll have to log out and back in for it to take effect.