Mix together all the ingredients for the reverse rub and set aside. This can be done well in advance and stored in the fridge for up to three days.
Season the steak with salt and place it on the preheated BBQ. Cook it on the first side until you develop a deep browning. Turn the steak and continue to cook until it is medium-rare. Place a thermometer in the thickest part of the meat and when it reads 130F take it off the BBQ and tent it loosely with aluminum foil for 15 minutes.
Toss all the ingredients for the tomato salad in a bowl. Add one tablespoon of the reverse rub mixture and mix together.
Place the meat on a cutting board and slather the top with two tablespoons of the reverse rub. Turn it over and repeat on the other side. Slice the steak against the grain.
Place the slice steak on a large platter and spoon the tomato salad down the centre.