1. In a large pot of boiling, salted water, cook the linguine until just done, about 12 minutes. Drain the pasta. Rinse with cold water and drain thoroughly.
2. Meanwhile, in another large pot, heat the oil over moderate heat. Add the pork, scallions, and ginger and cook, stirring occasionally, for 2 minutes.
3. Add the tomatoes, fish sauce, salt, water, and broth. Bring to a boil. Reduce the heat and simmer until the pork is just done, about 10 minutes. Stir the cooked linguine, bean sprouts, and lime juice into the soup. Ladle into bowls, top each serving with some of the cucumber and herbs, and serve with the lime wedges.
Wine Recommendation: More and more Asian fusion chefs are discovering how well riesling complements their food. Try a Mosel kabinett here to see how its sweetness balances the soup's salty flavors while the bright citrus flavors in both shine through.
Notes: Asian fish sauce is available at Asian markets and most supermarkets.