Steam bok choy until tender, crisp, about 5-8 minutes depending on the size. You can check tenderness by piercing the base of one of the bok choy with a fork or knife. Do not overcook. When done, drain. While bok choy is cooking, mix the canola oil, sesame oil, mirin, soy sauce, hot sauce, and rice vinegar together in a small bowl. Strain bok choy, toss with oil and mirin dressing, and serve.