Sure it is, that's what Ted Cruz did, they just had a big bonfire

If it was that simple, Conrad Black wouldn't have had to try to sue Chretien to obtain his British Baron Title. There is an application process.
The one, and only, way for your citizenship to be revoked is if you are found to have lied on your application.
Conservatives have tried to change this but it will not hold up to a supreme court hearing
Citizenship changes 'likely unconstitutional,' lawyers warn$1:
Under the proposed legislation, the government would have the power to strip Canadian citizenship from dual nationals "who were members of an armed force or an organized armed group engaged in armed conflict with Canada."
The government would also have the ability to revoke citizenship from those who has been "convicted of terrorism, high treason, treason, or spying offences, depending on the sentence received."
The Proposed changes are contained in Bill C-24 which has been passed but likely will not stand in court due to constitutional conflicts.
http://www.cbc.ca/news/politics/citizen ... -1.2627077Edit: This law has not yet been tried in court and so it is impossible to say for certain whether it would stand up to a supreme court challenge but most experts believe it would not.