This has been asked many times before, with the solution being fairly straightforward (e.g. Settings > Display, etc). Currently, VMware Fusion 10 provides an option to use all monitors in fullscreen mode.
View > Use all displays in fullscreen
This is useful if you want dual monitor support when you have two physical external monitors. However, I typically work with three external monitors and only want to use two of them for my guest virtual machine.
Is this possible? It seems previous versions of VMware allowed the user to explicitly set the number of monitors passed to the guest, but the latest release (10) seems like an "all or nothing" approach.