Place dried mushrooms in a bowl and pour boiling water over them. Let stand about 40 minutes while you prepare the other ingredients. Remove mushrooms from water with a slotted spoon and thinly slice, reserving water.

Place all of the prepared ingredients right near the stove. Heat a large wok or skillet not non stick with a lid over medium high heat. Swirl canola oil around. Add ginger and garlic and cook 30 seconds. Add sliced mushrooms, bok choy, soy sauce and two tablespoons of mushroom soaking water to the skillet. Stir briefly, cover and let cook about three or four minutes, until bok choy stem ends are crisp tender, stirring occasionally. Season with salt and pepper and transfer to a serving dish. Garnish with toasted sesame seeds.