At the moment, it isn't possible to run NCrunch from the command line. I do, however, understand the motive behind this. As there are differences between NCrunch's test environment and that of a standard test runner, it is desirable to be able to ensure code is NCrunch-compliant as part of a continuous integration process. This could be useful for teams where not all members are making use of NCrunch.
Unfortunately, NCrunch itself is designed to be fully continuous. The architecture of a continuous test runner vs a serial test runner is very, very different. Attempts have been made to produce a console variant but so far none of these have resulted in anything reliable enough to be used for a continuous integration process or build server. There is still the possibility of this area being explored more in future.