Cook pasta according to package directions. Remove noodles from water with a slotted spoon, reserving boiling water. Blanch asparagus in water for 30 seconds, until bright green. Drain and reserve 1/2 cup of cooking water.
Heat olive oil in a pan over medium heat. Add garlic and red pepper flakes and saute for 30 seconds. Remove from heat.
Add pasta, sun-dried tomatoes and asparagus and toss everything together. Pour in lemon juice along with additional cooking water if the dish seems too dry. Season with salt and pepper.