In a large pot of salted water, cook the pasta until just al dente. Drain and return to the pot. Cover to keep warm.
Meanwhile, in a large saute pan, heat the oil over medium-high heat. Add the pancetta and cook until golden brown, 3 to 4 minutes.
To the oil in the pan, add the onions and cook, stirring, for 2 minutes. Add the garlic and cook, stirring, for 30 seconds. Add the wine, 3/4 teaspoon salt, red pepper, lemon juice, and langoustines and cook, stirring, until the shellfish are pink and cooked through, about 5 minutes. Add the parsley and stir to combine.
Add the cooked pasta to the shellfish mixture and toss well to combine. Cook until the pasta is heated through, about 1 minute. Remove from the heat, add the lemon zest, and adjust the seasoning, to taste. Sprinkle with Parmesan. Spoon into individual pasta bowls or onto large plates, and serve immediately.