In a medium bowl, combine the fish sauce, water, 1½ tablespoons lime juice, vinegar, sugar, salt, and cayenne; set aside.
In a pot of boiling, salted water, cook linguine until al-dente, about 12 minutes. Drain, rinse with cool water, and set aside.
Meanwhile, in a wok or large frying pan, heat 1 tablespoon oil over medium-high heat.
Add the chicken and cook, stirring often, until just done, 3 to 4 minutes. Remove to a paper-towel lined dish; set aside.
Put the remaining oil in the pan, add garlic and cook, stirring constantly, for about 30 seconds, do not brown or burn.
Immediately add the pasta and fish-sauce mixture.
Cook, stirring constantly, until nearly all the liquid has been absorbed.
Stir in the cooked chicken.
Remove from heat. Stir in remaining lime juice, bean sprouts, and half the cilantro.
Garnish with remaining peanuts and cilantro.