Thai-style mushroom and tofu stir-fry

In a small bowl, whisk together the peanut butter, soy sauce, and lime juice until smooth. Add the water, sesame oil, cornstarch, and pepper flakes and whisk until blended. Coat a non-stick wok or large non-stick frying pan with non-stick cooking spray and heat over high heat. Add the mushrooms and stir-fry until lightly browned, about 4 minutes. Add the snow peas and continue stir-frying until the peas are tender-crisp, 2-3 minutes. Add the peanut butter mixture, and tofu and stir-fry until the sauce thickens slightly, about 1 minute. To serve, transfer to a bowl. Sprinkle with cilantro.