Whisk eggs, Parmesan, olive oil, cherry peppers, parsley, 1/2 teaspoon salt, and 1/2 teaspoon pepper in large bowl until egg is even yellow color; set aside.
Cook sausage in 10-inch nonstick skillet over medium heat, breaking up sausage with wooden spoon, until fat renders and sausage is about half cooked, 3 to 5 minutes. Stir in garlic and cook for 30 seconds. Remove skillet from heat. Transfer sausage mixture (some sausage will still be raw) to bowl with egg mixture and wipe out skillet.
Bring water, pasta, vegetable oil, and 3/4 teaspoon salt to boil in now-empty skillet over high heat, stirring occasionally. Cook, stirring occasionally, until pasta is tender, water has evaporated, and pasta starts to sizzle in oil, 8 to 12 minutes. Reduce heat to medium and continue to cook pasta, swirling pan and scraping under edge of pasta with rubber spatula frequently to prevent sticking (do not stir), until bottom turns golden and starts to crisp, 5 to 7 minutes (lift up edge of pasta to check progress).
Using spatula, push some pasta up sides of skillet so entire pan surface is covered with pasta. Pour egg mixture over pasta. Using tongs, lift up loose strands of pasta to allow egg to flow toward pan, being careful not to pull up crispy bottom crust. Cover skillet and continue to cook over medium heat until bottom crust turns golden brown and top of frittata is just set (egg below very top will still be raw), 5 to 8 minutes. Slide frittata onto large plate. Invert frittata onto second large plate and slide it browned side up back into skillet. Tuck edges of frittata into skillet with rubber spatula. Continue to cook second side of frittata until light brown, 2 to 4 minutes longer.
Remove skillet from heat and let stand for 5 minutes. Using your hand or pan lid, invert frittata onto cutting board. Cut into wedges and serve.