Hi,
At present, I know of no workaround.
To handle .NET Core, NCrunch needs to integrate with the new VS project system.
It then needs rewired handling of the load process, integration with the new build logic, cross-compilation of all runtime components to target .NET Core, and a new task runner that can enable the .NET Core environment. Because there are so many tool steps that need to change to support .NET Core, I don't expect there will be a feasible workaround that will allow NCrunch to use it prior to the proper support being introduced.
Of course, someone may prove me wrong :)