Every menu item corresponds to a command. The easiest way to find which menu item maps to which command is to enter
sublime.log_commands(True) in the console and invoke the command as you normally would. That works for key bindings, mouse bindings and the command palette too, of course.
The other way is to track down where the resource is specified (everything in ST that's calling a command has this referenced somewhere), e.g. by inspecting
The docs will include this information at some point.