Cook the noodles as the label directs, then drain and rinse under cold water. Meanwhile, toss the pork with 1/4 teaspoon salt, pepper to taste and 2 tablespoons cornstarch in a bowl. Whisk the chicken broth and the remaining 1 tablespoon cornstarch in another bowl.
Heat a large nonstick skillet over high heat. Add 1 teaspoon vegetable oil, then add the pork and stir-fry until lightly browned, about 5 minutes; transfer to a bowl. Add the remaining 3 teaspoons vegetable oil to the pan, then add the scallion whites, ginger and garlic; reduce the heat to medium and cook, stirring occasionally, 2 minutes. Stir in the vegetables and 3 tablespoons water and cook, stirring occasionally, until the vegetables are crisp-tender, about 4 minutes. Add the broth mixture to the pan and bring to a boil; cook, stirring occasionally, until slightly thickened, about 5 minutes.
Return the pork to the skillet along with the noodles, lime zest and 1/4 teaspoon salt and stir to heat through. Stir in the scallion greens. Divide among bowls and serve with lime wedges.