In a medium sauce pan, heat the canola oil on medium heat. Add the onion and cook until soft. Add the garlic and cook for 1 minute. Add chicken broth, chili sauce, soy sauce, brown sugar, Chinese five-spice powder, tomato sauce, honey, and molasses. Cook until slightly reduced. Add the rice wine vinegar, sesame oil, and sherry. Simmer on low for approximately 15 minutes.
In a small bowl, stir together the cornstarch and water. Turn the heat up to med/hi and add cornstarch mixture, stirring constantly for one minute. Remove from heat.
Variation: If you want a thinner sauce, omit the cornstarch mixture.