DO NOT spread it around. The pre-applied compound is a pretty thin layer to start off with and it needs to be present only in the area where the core enclosure itself will contact the heatsink. What little excess there may be will sort of ooze out when the heatsink is installed leaving an extremely thin layer between the actual core enclosure of the CPU and the heatsink. The whole purpose of the thermal compound is to compensate for any imperfections in the surface of the core where it should be in contact with the heatsink. The compound is a much better conductor of heat than air so you have maximum surface contact when any small gaps are filled with the compound and dramatically better heat transfer than a dry surface to surface joint.
Some daring souls have actually lapped (polished) the surface of their CPU's core enclosure to eliminate as many imperfections as possible and eliminate any "voids" (indentations) in the surface which would reduce the contact area.
The actual core enclosure of the chip is the smallish (approx 1/2" X 1/2"

raised area of the CPU module.