Place the sliced onion in a small bowl and season. Take the zest from one of the lemons and squeeze the juice. Set the zest aside for later and pour the lemon juice over the onion. Leave to infuse for 20 minutes.
Squeeze the juice from the second lemon and use to make a dressing with the olive oil, capers and seasoning. Mix thoroughly and set aside.
Mix the spelt with the chickpeas in a large bowl. Stir in the dressing and the onions (with their juices). Finally add the beetroot, cockles and parsley and stir to combine.
Heat a frying pan over a medium heat and fry the halloumi for 1-2 minutes on each side until golden brown. Sprinkle with the lemon zest and serve on top of the salad.