To prepare the noodles, bring a large pot of water to a rolling boil. Stir in the noodles. Cook until just done, about 4 minutes for fresh and 10 minutes for dried. Remove from the heat, rinse in cool water, and drain completely.
Heat the oil in a skillet over medium heat. Add the garlic, and stir until fragrant and golden (not brown), for about 20 seconds. Add the sesame oil, soy sauce, sugar, chile flakes, and scallions. Add the noodles and coat them evenly with the sauce. Transfer to a serving platter. Place in a warm oven while the crab is being prepared.
Crab- To prepare the crab, clean the crab and separate the claws from the body. Crack the claws and legs, and cut the body into 4–6 pieces.
Heat the oil in a large wok or skillet over medium heat. Add the garlic, shallot, and ginger and then quickly stir-fry until golden, about 10 seconds. Add the soy sauce, salt, pepper, sugar, chiles, scallions, and crab. Stir-fry until shells begin to turn red. Add sherry and chicken broth. Cover and let simmer for 7 minutes. Remove cover and stir in cornstarch. Stir until saucy, about 2–3 minutes.
To serve, transfer the crab to the platter containing the garlic noodles and arrange on top. Garnish with the cilantro and serve immediately with lots of napkins!