In a medium mixing bowl, combine lemongrass, garlic, green onions, olive oil, soy sauce, sesame oil, and crushed red pepper.
Whisk all ingredients until completely combined.
Place the pork tenderloins in a one gallon storage bag that can zip shut. Pour the marinade in with the tenderloins and seal shut, removing any excess air. Allow to marinade in the fridge for at least 4 hours up to overnight.
Preheat oven to 400°F. Remove the pork tenderloins from the marinade and place on a baking sheet lined with parchment paper. Roast the pork tenderloin for approximately 20-25 minutes until it reaches an internal temperature of 145°F. Remove from oven, cover with aluminum foil, and allow to rest for at least 5 minutes before slicing.