Just got a Project Tango Development Kit tablet and have worked through some of the demos and examples.
Some older blog posts use the log files from a "Tango Map
Tango Mapper is an internal tool, and it's currently not public to developers. I think the best way to log the point cloud data is using the c or java example code provided, and maybe do some small modification to log the data to a file.
c example: https://github.com/googlesamples/tango-examples-c
java example: https://github.com/googlesamples/tango-examples-java