Bring a pot of salted water to a boil over medium-high heat. Fill a large bowl with ice water and set aside. Shock the green beans in the boiling water until bright green and just tender, about 1-2 minutes. Drain and immediately plunge into ice water. Set aside.\nUsing a sharp knife, carefully slice the flank steak across the grain into long, thin strips, about ¼-inch thick. Season well on both sides with salt and pepper. \nIn a small bowl, whisk together the garlic, ginger, ¼ cup This Little Goat went to Tokyo sauce, vinegar, and ½ tsp salt. \nCoat a large wok or skillet with about 1 teaspoon sesame oil and heat over high heat. Once the oil is shimmering, add the beef and remaining 1 tablespoon Tokyo sauce to the skillet. Sear the meat, allowing it to achieve a deep glaze from the sauce, until golden brown on all sides, about 5 minutes. Transfer to a plate. Do not wipe out the skillet.\nDrain the green beans and pat to dry completely. \nAdd remaining 1 teaspoon sesame oil to the skillet (over high heat) and add in the green beans, shallots and Tokyo sauce mixture. Sauté until the beans are well coated and beginning to color, about 3-4 minutes. Return the beef to the skillet and continue stir-frying until everything is well combined and cooked through, about 1-2 minutes more. \nStir in the sesame seeds. Serve warm, alongside cooked rice or noodles, if desired.