Put the onion in a bowl with a few ice cubes and the vinegar, then pour in 120ml water and stir. Leave to sit for 10 minutes – this removes the onion’s raw heat and crisps it up even further.
Meanwhile, pour the olive oil into a large heavy-based saucepan over a medium-high heat. Add the chorizo and sear all over, then turn the heat down to medium and add the garlic, cumin and chilli flakes. Stir for a few seconds, then add the chickpeas, honey and 3 tbsp vinegar. Stir to combine, season, then cover and simmer gently for 10 minutes. Remove from the heat and leave to cool briefly.
Drain the onion and add to the mixture along with the peppers, tomatoes, olives and herbs. Taste and add more salt and pepper if you like. Serve warm or at room temperature.
