Possible to get touch area data?

I'd like to get information on the area size of a touch on mobile devices (the "cloud" of points that are used to approximate the pixel-point that is used as the pointer).

The application is for a game where I'd like everything under a player's finger to react: sometimes the player will poke straight downward for a precise hit, and sometimes players will mash their finger parallel to the screen for a wider hit.

I don't see any tools in the Unity API that cover this, and searching for it is particularly difficult because it's hard to search for this without turning up tons of results on multitouch, which is not what this is about.