Canada and most other jurisdictions internationally have opted to implement the double criminality principle through the conduct-based approach that asks whether the conduct in the foreign jurisdiction could amount to an offence under domestic law.
In the extradition proceedings for Wanzhou Meng, it was alleged that Huawei misled a U.S. bank about Huawei's connections with Iran. The bank was subject to the Iranian Transaction and Sanctions Regulations and a deferred prosecution agreement that required the bank to not provide financial assistance with certain connections to Iran (United States v Meng, 2020 BCSC 785).
Ms. Meng's alleged conduct would have amounted to fraud in the U.S.
But, the alleged misstatements would not have been material in Canada and would not amount to fraud:
The parties agree ... that ... financial institutions operating in Canada would not have been at risk of penalty for engaging in financial transactions or providing credit to companies doing business in Iran.
It would have been legal for Ms. Weng to submit the offending documents to a bank in Canada.
Nevertheless, the double criminality requirement was met.
The court rejected a fine parsing of the "conduct." It did not consider it at a "narrow" scope of the precise misstatement. This would "unduly isolate" the facts from the context of the fraud. Instead, the court took a broader view of the "conduct." The question was more properly whether materially false statements to a bank could constitute fraud in Canada.
So, whether double criminality is met in your circumstance will depend on the scope at which the court views the conduct.
If the conduct is conceived of as the possession of pepper spray specifically, then dual criminality will not be made out.
If instead the conduct is considered more broadly as the possession of a prohibited weapon, then dual criminality will be made out.