Heat canola oil in a large saute pan over high heat. Sauté garlic and ginger for about 30 seconds, until fragrant. Reduce heat to medium high and add chicken. Cook, stirring frequently to break up chicken, until it's no longer pink.
Add cabbage, carrots, mushrooms and scallions and stir well until vegetables start to wilt.
Add hoison sauce, sesame oil, and season with soy sauce to taste.
Remove chicken from heat, and let cool for about 5 minutes.
Spoon about 3 tablespoons of chicken mixture into the center of each lettuce leave and serve.
To eat, roll leaves, burrito style.
Notes
To save time, use shredded carrots and cabbage from the produce department.