Preheat oven to 400ºF (205ºC). Line a large baking sheet with parchment paper and set aside.
ROAST BRUSSELS SPROUTS: Trim the bottoms of the brussels sprouts and chop them in half. Toss them with the olive oil and sprinkle with a small pinch of salt. Spread brussels sprouts onto the lined baking sheet and bake for 15 to 20 minutes, until the leaves have browned.
PREPARE SAUCE: In a small bowl, mix the soy sauce, shaoxing wine, vinegar, honey and sesame oil together. In another small bowl, mix the water and cornstarch together until the cornstarch is well dissolved. If you accidentally mixed the cornstarch with the soy sauce mixture, don't worry, just stir until it's well incorporated.
Heat the canola in a small saucepan over medium heat. Add the minced garlic and ginger and cook until the spices are fragrant, about 1 minute. Add the soy sauce mixture, then add the cornstarch mixture and the red chili flakes. Bring the sauce to boil and let it simmer for another 2 to 3 minutes, until the sauce thickens.
MIX BRUSSELS SPROUTS WITH SAUCE: When the brussels sprouts are done, pour them into a large bowl. Pour about 2 to 3 tablespoons of the sauce onto the brussels sprouts and stir. Feel free to add more sauce if you like. If you prepared the sauce ahead of time, and it's very thick, just warm it up a little again before stirring it with the brussels sprouts.
Sprinkle sliced scallions and sesame seeds to garnish.