Bring a large pot of water to a boil. Salt the water; add pasta, and cook until al dente. Drain. While the spaghetti is cooking, heat oil in a large saucepan over medium heat. Add the lime rind, garlic, chile pepper, and capers; cook until fragrant, about 1 minute. Add prosciutto, and cook until crisp, about 2 minutes. Add drained spaghetti, and toss to coat and heat through.
Toss the arugula and lime juice with the pasta, and pile into serving bowls. Top with feta cheese and a little of the marinating oil. Sprinkle with pepper, and serve immediately.
Note: Slab bacon, rind removed, may be substituted for the prosciutto.
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