Several of the PCs, laptops out there don't have a true multitouch, they have a simulated touch under the hood, which take the touchs as click events, so in that way simple click(tap) or two finger gestures should work on the web player.
Not sure what you want to achieve or which gestures you want to incorporate.
I have tested multitouch but in a windows build, no with the web player.
When you say doesn't seem to work is a confirmation or you haven't tested.
I suspect that TouchScript (TUIO) should work on most cases for advanced touch screens not cheap, non standard windows pc screens. The best bet is to code a script in some multitouch screens using the Input.GetTouches and the moving fwd to touchScript.
Also take a look at gestureworks.com they have a library that can be used for touch gestures in unity, aside from touch script is looks the more robust for me so far. I still have to tested.
So far I have asked unity folks and they have confirmed touch is working on windows surface in a windows build not sure with web player. Ask also there your question.
Also look at this discussion which are not related to web player but they list some workarounds.
http://answers.unity3d.com/questions/220548/using-microsoft-surface-20-with-unity.html