Changing Screen Resolution is a function of the OS not Fusion and it is done the same way as if it was a physical machine so... Click > Start > Help and Support > type resolution in the Search text box and press Enter then click Change your screen resolution under Search Results.
Also installing VMware Tools will improve your ability to change resolution by resizing the Virtual Machine Display just like you would resize any other window and provide higher resolutions by installing the driver for the VMware SVGA II Graphics Adapter.