BEIJING—The second of Canada’s “two Michaels” went on trial in Beijing on Monday after being detained for more than two years in apparent retaliation for the arrest in Vancouver of a top executive of Chinese telecom giant Huawei. The trial of former diplomat Michael Kovrig on spying charges follows an initial hearing in the case of Canadian businessman Michael Spavor, who faces similar charges, in the northeastern city of Dandong on Friday. Canadian diplomats have been denied access to the trials with the explanation the hearings were being held behind closed doors because of alleged national security concerns. Diplomats and journalists have showed up nonetheless to seek information and show support. Outside Beijing’s No. 2 Intermediate Court, Jim Nickel, the Canadian Embassy’s deputy chief of mission, said he’d been told the trial had begun, but was barred from entry in what he complained was a violation of China’s international and …