Fill a large pot with water and bring to a boil to cook the pasta. Combine the sun-dried tomatoes, garlic and cayenne and ancho peppers in a small bowl and cover with the boiling water. Set aside and allow to cool to room temperature.
Trim the spring onions. Remove the dark green tops and set aside. Cut the white and light green sections into 1/4 inch slices.
In a medium saute pan, heat the olive oil over medium heat. Add the white and light green scallions and saute for 3 to 5 minutes or until the scallions are golden brown. Add the pepper and sun-dried tomato mixture and stir well to deglaze the pan. Bring to a boil, reduce the heat and simmer for 15 minutes. Remove the pan from the heat and mash the sauce well with a potato masher. Return to very low heat to keep warm while you prepare the pasta.
Cut the dark green scallion tops into 1/4 inch slices and set aside. Cook the angel hair al dente, according to the package directions. Drain well, rinse to remove starch, and drain again. Toss with the sauce, garnish with the scallion tops and serve immediately.