Junio posted a time of 35.02 seconds, finishing behind Ronald Mulder of the Netherlands, who won in 34.96. German Nico Ihle was third in 35.10.
"I'm really happy with the result from today, a bit surprised maybe but I felt I still had some good skating left in me after Olympics," Junio said. "It's nice to come here after the Games with that experience under my belt and use as a learning experience to improve my results internationally.
"I wanted to end the season strong and this is a good start."
Junio made headlines at last month's Winter Games in Sochi when he gave up his spot in the men's 1,000-metre race to teammate Denny Morrison of Fort St. John, B.C., who went on to win the silver medal.
Junio earned his third career World Cup medal, all coming over 500 metres.
The Canadian won gold in Salt Lake City in November 2013 and silver in Nagano, Japan in December 2012.
William Dutton of Humboldt, Sask. was 13th in 35.44 seconds while Edmonton's Jamie Gregg was 16th in 35.58.
Morrison was sixth in the 1,000-metre race while Gregg finished 13th.
In the women's competition, Calgary's Kaylin Irvine was 13th in the 500 while Ottawa's Ivanie Blondin was 12th in the 3,000-metre race.