Soak noodles in hot water until slightly limp; drain and set aside. In a medium bowl, combine fish sauce, soy sauce, tamarind juice, vinegar, sugar, and radish; stir until sugar is dissolved and then set aside. Prepare and measure all of the other ingredients before beginning to cook.
Heat oil in a wok or large skillet over high heat. When oil is hot, working quickly, add garlic and shrimp and toss with wooden spoons until shrimp are about halfway done. Add cayenne pepper and paprika and toss to combine. Add noodles and radish mixture and toss well. Add bean sprouts and tofu and toss. Add peanuts and garlic chives and toss. When shrimp is just cooked through and all the ingredients are heated through, remove from heat. Garnish with shredded eggs and lime wedges, if desired. Serve immediately.