Bring a medium saucepan of water to a boil. Add the noodles, stir and remove from the heat. Let sit until softened, about 5 minutes. Drain and rinse under cold water; drain well. Cut into shorter lengths using kitchen shears.
Meanwhile, combine the vinegar, lime juice, fish sauce, sugar and 2 tablespoons water in a small bowl and stir until the sugar is dissolved.
Divide the lettuce among bowls and top with the noodles, carrots and cucumber; set aside.
Cook the pork in a medium nonstick skillet over medium-high heat, stirring occasionally, until hot and crisp, about 8 minutes. Divide among the salads. Drizzle with the dressing and top with the herbs and peanuts. Drizzle with Sriracha.