If your CFI is suggesting performing stalls with one engine inoperative, then you should have a little talk with your CFI.

This is taken right from the FAA's PTS:

XI. AREA OF OPERATION: SLOW FLIGHT AND STALLS
NOTE: The examiner shall select at least one TASK. Stalls shall not be
performed with one engine at reduced power or inoperative and the other
engine(s) developing effective power.


http://www.faa.gov/education_researc...-S-8081-6C.pdf

page 2-41 or page 169 on the PDF file

You CAN do stalls in a multiengine airplane, it just needs to be done with both engines running at reduced power.