Sharpe, from Comox, B.C., finished first with a score of 93.80. Ayana Onozuka of Japan was second at 90.40 while Brita Sigourney was third at 86.40.
Sharpe said she was pleased just to make it into the finals against such a strong field.
"That in itself was something so big for me to accomplish," she said on a conference call. "I could not be happier with my result for this contest."
Riddle, from Edmonton, captured the men's gold with 95.00 points. Americans David Wise (94.20) and Alex Ferreira (87.40) took silver and bronze respectively.
"I actually landed all three runs, which for me is kind of rare," Riddle said. "That was probably my favourite part of the night. But my goal tonight was just to go out and put my run down.
"It took me three tries so I'm definitely loving the three-run format in the World Cups this year. Everyone skied so (well) and I'm unbelievably happy to come out on top."
It was Riddle's first podium appearance since winning silver last year at the Sochi Olympics.