Place 1 1/2 pounds thinly sliced steak and 8 ounces sliced mushrooms in a large bowl and sprinkle with 4 teaspoons cornstarch, 4 teaspoons soy sauce and a generous amount of salt and pepper. Toss to coat and set aside to marinate at room temperature for 15 minutes, or in the fridge for up to 5 hours.
Toast 2 tablespoons sesame seeds in a dry skillet until golden brown, shaking pan frequently to prevent burning. Remove from heat right when they become fragrant but haven't gotten to brown yet. Let cool in pan and finish toasting continuing to stir every once in a while.
Combine 2 tablespoons orange zest, 1 cup orange juice, 2 tablespoons red wine vinegar, 2 tablespoons Shaoxing, 2 teaspoons Sriracha, and 2 tablespoons oyster sauce in a medium bowl and mix well.
Heat 1 tablespoon of the peanut and 1 tablespoon sesame oil in a large non-stick frying pan over high heat. Once shimmering add half of the meat-mushroom mixture. Spread in an even layer and let cook, undisturbed until lightly browned. Give a stir and let brown on other side. Remove from pan and repeat with remaining oils and beef mixture.
Return first batch of beef to the pan and add 2 tablespoons minced ginger and 2 cloves minced garlic and stir-fry for about 30 seconds or until ginger is beginning to brown. Give sauce a stir then add sauce to pan and cook, stirring, until sauce starts to boil.
Sprinkle sesame seeds and green onions over top and serve with steamed rice and sauteed bok choy or spinach.