A search via google for "linux canadian tax software" turned up some web-based filing applications (for a fee), as well as one called Futuretax
which is free to download. They claim it runs under wine on Linux systems.
FutureTax runs on Windows 95, 98, ME, NT, 2000, XP, Server 2003, Vista and Windows 7.
FutureTax also runs with Wine emulator 1.0.1 on Linux, FreeBSD and Solaris.
It requires 128 MB memory, 25 MB free hard disk space and an internet connection to submit tax returns online.
FutureTax does not support Apple Macintosh operating system.
Returns may also be printed to mail in rather than filing online.