Who knew you could enjoy the vegetable part of a salad more than the meat part?
In a medium bowl, whisk 2 tbsp. oil, the chile, fish sauce, lime zest and juice, and sugar. Set the dressing aside.
In a cast-iron skillet, heat the remaining 1 tbsp. oil over medium-high. Season the steaks. Cook the steaks until cooked to desired doneness, about 5 minutes per side for medium-rare. Remove from heat and let rest for 10 minutes. Thinly slice the steaks and transfer to a platter.
Toss the cilantro, basil, mint, and onion with the dressing. Pile the salad on top of the steaks.