In a large bowl, soak noodles in warm water for 15 minutes.
Meanwhile, in a medium bowl, toss tofu with marinade: 1 Tbsp (15 mL) of the soy sauce, plus lemon juice, lemon-grass and ginger paste, and sesame oil. Heat a large non-stick wok or sauté pan over medium-high; add tofu and its marinade. Cook, stirring often, until tofu is light golden, about 5 minutes. Push tofu to one side; add mushrooms. Cook, stirring, until mushrooms are golden, about 5 minutes.
Stir in drained noodles, coconut milk, tomato paste and remaining soy sauce; toss everything together and cook for 1 minute. Stir in peas; cook for 2 minutes, or until peas are tender-crisp. Divide among 4 plates and sprinkle with cilantro.
Per serving: 285 calories, 13 g protein, 10 g fat (4 g saturated fat), 37 g carbohydrates, 3 g fibre, 0 mg cholesterol, 345 mg sodium.