Place beef steak on grill and cook, covered, 13-16 minutes over medium heat on preheated gas grill for medium rare (145°F) to medium (160°F) doneness, turning occasionally.
Meanwhile, whisk all dressing ingredients in medium bowl until smooth or shake together in a mason jar; set aside. Arrange lettuce on serving platter; arrange avocado, carrot and bell pepper over lettuce.
Cut steak into slices; season with salt. Place beef over salad. Drizzle with dressing. Sprinkle with peanuts, if desired. Serve immediately; squeeze lime wedges over salad, as desired.
Recipe by Mandy's Recipe Box at https://mandysrecipeboxblog.com/easy-sirloin-thai-salad/