Combine the parsley, breadcrumbs, and orange zest in a small bowl. Set aside.
Add 2 quarts of water, the salt, and linguine to an 11-inch high-sided pan. Cover and bring to a boil over medium-high heat. Reduce the heat to low and cook for 4 minutes or until the pasta is al dente.
Meanwhile, cook the sausage, crumbling with a wooden spoon, in a 12-inch cast-iron skillet over medium-high heat until brown. Add the green onions and reduce the heat to low.
While the pasta and sausage are cooking, whisk together the eggs, cheese, and pepper in a medium bowl.
Drain the pasta, reserving 1/4 cup of the starchy water. Add the pasta to the sausage, tossing the pasta to coat in the fat.
Kill the heat, add the egg mixture. Toss to thoroughly combine, thinning as needed with the reserved pasta water.
Serve immediately with a generous sprinkle of the parsley mixture.