Bangladeshi citizen, permanent resident of Canada planning to visit Beijing and Hong Kong?

I'm afraid you have to get two separate entry permits for these places. To apply for the entry permit for Beijing, you should send your documents to the CVASC office which is in charge of your residence area. As for applying the HK entry pemit, the application should be submitted to the Chinese embassy or consulate in Canada or you can choose to send it directly to the HK Immigration Department.