Are there any open libraries or opensource codes available for finger position detection using Kinect ? I have tried searching OpenNI and other libraries for Kinect but could'nt find one.
I was looking into this a few years ago, you can check out this post from then which includes a few options.
Links may be a bit outdates, for example Apple bought OpenNI, so the Forth ICS project can now be found here
You didn't mention which version of the kinect, so I'll assume it's the original kinect for xbox 360.
If you're not constrained to using kinect only, you might actually want to try the Intel RealSense SDK as it already includes hand tracking(pdf tutorial link) and the c++ sdk has wrappers for c#/java and makes the data available through websockets.