How can I find a list of Canadian private companies that use Canadian government open data?
opendata500.com, and in particular Open Data Canada 150 might be useful for you.
The Open Data 150 is a joint project between The Govlab and Canada’s Open Data Exchange (ODX), supported by the Federal Economic Development Agency for Southern Ontario and ThomsonReuters. It is the first comprehensive, internationally comparable mapping of Canadian companies that use open data to: launch new products and services; create commercial and nonprofit ventures, optimize their business processes, do research, make data-driven decisions, and solve complex problems.