The plight of the “Two Michaels” might seem a distant memory for most Canadians. Yet barely two years after China released these two high-profile hostages from prison, Canadians have reason to fear a repetition of Beijing’s strong-arm tactics — through the heavy hand of Hong Kong. Where once Canadian citizens on the mainland were considered fair game for domestic hostage-taking — notably Michael Kovrig and Michael Spavor — now it is Hong Kong dissidents seeking sanctuary in Canada who are being targeted for bounties both exorbitant and extraterritorial. For a reward of $1 million in local currency (about $170,000 in...