To make the quick pickle, put the cider vinegar, salt and sugar in a measuring jug or bowl and stir until the salt has dissolved. Add the coriander seeds, fennel seeds and red onion and press down to ensure all the onion slices are covered in the pickling liquid. Set aside for 15 minutes.
Put the broad beans into a small saucepan, cover with water and bring to the boil. Simmer for 3-4 minutes, or until the beans are soft, then rinse with cold water and drain.
To make the salad, combine the radishes, chickpeas, lettuce, tomatoes and broad beans in a bowl. Add the olive oil and a big pinch of salt and pepper and toss to combine.
Dry fry the halloumi in a pan for 4-5 minutes over a medium heat, or until all the liquid has been released and the halloumi turns golden brown. Flip over and cook for a further minute or two.
Divide the salad between two bowls, top with the halloumi slices and finish with the pickled red onions.