Step 1 To make your dressing, zest a lemon directly into a large bowl then add the juice of the lemon. Add minced garlic, olive oil, dried oregano, salt, and pepper, and mix well with a fork. Finely slice a red onion and add to the dressing, mix well. Step 2 Cut cucumbers in half length wise, then into quarters. Pick celery leaves from the stalk and set aside, then cut the remaining celery stalk into quarters. Pick parsley leaves from the stems. Step 3 Place the cucumber, celery stalks and leaves, and parsley onto a large chopping board with olives. Using your biggest knife, chop everything together into small pieces, roughly 2cm. Step 4 Transfer the chopped salad to the bowl with the dressing. Drain and rinse the borlotti beans and add them to the bowl, along with half a teaspoon of chilli flakes, if using. Drain the excess oil from the tuna can, add to the bowl, and mix gently. Add salt and pepper to taste, be generous with the seasoning. Step 5 Divide the salad between bowls and crumble the feta on top to serve.
