Sprinkle the Chillichup rub over the steaks and marinade for at least an hour. Place a non-stick frying pan on a high heat. When the pan is very hot, carefully add the steaks to the pan, making sure not to move or turn too often. Cook to your preference. Allow the steaks to rest, out of the pan, for at least 5 minutes. Arrange the watercress, rocket and spring onions on a platter. Slice the steak and rest over the salad. Be sure not to throw away any left over pan juices as these can be used to dress salad along with a drizzle of olive oil.