1. If you are making the tuna, start by finely slicing the spring onions, then place in a bowl with the tamari and add the tuna steaks. Using your hands, rub the tuna so that it is well coated with the marinade and set to one side.
2. Rinse the rocket leaves and divide them between your two bowls.
3. Remove the seeds from the pomegranate. A great way to do this is by filling a bowl with cool water. This will stop you, your clothes and your kitchen from getting covered in juice! Cut the pomegranate in half then submerge one half under water to remove the seeds. The pith will float and the seeds will sink, making it easy to separate them before draining. Repeat with the other half.
4. Finely slice the spring onion and radishes.
5. Remove the shells from the pistachios and cut them in half lengthways.
6. Peel the beetroot and grate it using the regular side of a cheese grater.
7. Once you have prepared all off the salad ingredients you can add them to the bowls of rocket.
8. Prepare the dressing by combing the lemon juice, tahini and olive oil and mixing well.
9. If you are adding tuna, heat a small amount of oil in a griddle or frying pan. Once the pan is hot, add the tuna steaks. After about 30 seconds turn the steaks over. Allow them to cook for a further 30 seconds so that only the outsides have been seared.
10. Remove the tuna from the pan and use a sharp knive to finely slice the steaks.
11. Add them to the salad and pour over the dressing before serving.