Cook the rice noodles. Place noodles in a container or pot and cover with very hot water. Check after 25 to 30 minutes. If ready, drain and rinse with cold water, set aside.
Add 2 tablespoons of oil to a skillet and heat to medium/low. After a few minutes, add the onions, garlic, serrano and red pepper flakes. Saute for 5 minutes. Add the other peppers, season lightly with salt and pepper. Turn heat up and saute for 2 minutes.
Zest the lemon and set aside. Whisk the cornstarch with 1/3 cup of water and lemon juice until smooth, set aside.
To the pan, add the butter, chicken and asparagus. Toss to combine. Add in zest and cornstarch mixture, stir well. Cook for just a minute to thicken the sauce, taste for salt. Fold in the noodles, remove form heat and toss to combine. Fold in the parsley or cilantro, serve right away. Yields 4 servings.