Brush the steaks with oil and season with salt and pepper.
Griddle the steaks in a smoking pan for 3 to 6 minutes per side.
Rest the meat in a warm place for five minutes.
Finely slice Chinese leaf and shallots, and wedge the tomatoes.
De-seed the cucumber and slice on the diagonal.
Slice spring onions on the diagonal and tear the herb leaves.
Mix all vegetables and herbs in a large bowl.
Combine palm sugar and lime juice in a small bowl until dissolved.
Whisky in the fish sauce and chopped chillies to the dressing.
Thinly slice the steak on the diagonal.
Toss the beef and any resting juices with the salad and dressing.
Serve on a large plate with lime wedges.