Add .5-1" of water to a large pot, then place an open steaming basket in the pot so it is above the water to steam the wings. Bring the water to a boil, reduce the temp to medium and add the wings (do not over crowd, can be done in batches). Steam for 10 minutes.
Pat the steamed wings dry and place on a rack to dry for 1 hour. (use a baking sheet with tinfoil, topped with a few layers of paper towel. Put a wire rack on top of the paper towel.)
Combine the salt, peper, and baking powder.
Once cooled and dried, preheat oven to 425, toss the wings with the baking powder mix, remove the paper towel from the sheet pan, return the wings to the rack/pan and place the wings in preheated oven. Cook for 20 minutes, flip the wings and cook for 20-30 minutes more.
While the wings are cooking make the sauce.
In a saucepan saute the shallots, garlic and ginger until fragrant. Add the Mirin, Sake, Rice wine vinegar, honey, brown sugar, soy sauce, oyster sauce and ketchup. Bring mix to a simmer, stirring as needed, reduce by half. Add lemon juice to taste, and sesame oil, remove from heat.
When the wings are cooked, add some sauce to a large mixing bowl and toss with the wings.
Top with toasted sesame seeds and green onions to serve.
