How to Make It
Preheat the oven to 325°. Put the duck legs in a medium enameled cast-iron casserole. Add both soy sauces, the black vinegar, sake, sugar, onion, star anise, ginger and garlic. Add enough water to just cover and bring to a boil. Cover the casserole and transfer it to the oven. Braise the duck for 1 1/2 hours, or until it is very tender. Remove the duck legs from the liquid and let cool. Discard the duck skin and braising liquid. Pull the meat from the bones in large shreds.
In a medium bowl, whisk the rice vinegar with the canola oil and the 1/4 teaspoon of powered green tea. Season with salt. Add the Asian pear, mizuna and cabbage and toss. Transfer the salad to plates and top with the shredded duck. Sprinkle with green tea powder and serve.
Mushroom soy sauce is dark soy sauce flavored with straw mushrooms. Look for it in Asian markets.