Trim any visible fat from steaks and season on both sides with salt, pepper and chili pepper paste. Heat half of vegetable oil in a large skillet on high heat. Sear steaks (in batches, if necessary). For medium rare, cook for 5 to 7 min. per side, or until instant-read thermometer reaches 145°F (63°C). For well done, cook 9 min. per side, or 170°F (77°C). Add remainder of oil as needed.
Remove steaks and allow to rest for 5 min. Meanwhile, cut lettuce into quarters and place on four plates. Drizzle with Thousand Island dressing.
Slice steaks across the grain and divide among the four plates. Sprinkle with parsley and serve with potatoes or pasta.