Heat grill to high. Lightly season the steaks, then grill on each side for 2-3 mins for medium-rare, or longer if you like. Mix the lime juice, fish sauce, sugar and chilli together in a jug. Tip the salad, carrot and beansprouts into a bowl, then add the dressing, tossing everything together. Divide between four plates.
Thinly slice the beef and add to the salad. Some steamed rice flavoured with rice vinegar is a good side dish.