CodeWarrior and Kinetis Design studio are different tool chains (gcc) and different tool chain integration (the compiler/linker panels, etc).
So you cannot use CodeWarrior projects directly in Kinetis Design Studio and vice versa.
Have a look in C:\Freescale\KDS_2.0.0\doc\pdf\kds_porting_guide.pdf how to import and port a project.
That PDF is available on the Freescale KDS (http://www.freescale.com/kds) documentation page too:
http://cache.freescale.com/files/microcontrollers/doc/user_guide/KDS200PUG.pdf?fasp=1
But in general the best way is to create a new project in Kinetis Design Studio,then copy over all the sources.
If using Processor Expert project, then this article could be helpful for you: Export and Import Processor Expert Component Settings | MCU on Eclipse
I hope this helps,
Erich