Toss flank steak in the cornstarch, soda, and sugar. Cut the fresh chow fun noodles to 1 1/4 inches thick. Heat the vegetable oil in wok until hot. Fry the noodles until crisp, remove and drain on paper towels. In the jar of a blender add 1 stalk lemon grass, cut into pieces, 3 kafir lime leaves, 2 tablespoons brown sugar, 1 tablespoon Thai shrimp paste, 1 shallot, sliced thin, 1/2 cup dry Thai chilies, rehydrated. Puree. Add 2 cups coconut milk. Pour out the oil from the wok. To the wok, add flank steak, 1 bunch scallions, 1 bunch asparagus, blanched and cut on the bias, and 1 tablespoon garlic, minced. Wok fry until tender, about 2 minutes. Add chili sauce. Serve the steak and asparagus on top of a bed of fried chow fun noodles piled high. Garnish with Sichuan black beans, Thai basil, 1 bunch cilantro, shaved scallions, and 5 sprigs of mint.