2 cucumbers (approx 700g/1lb 9oz)
陆 bunch dill (about 10g/鈪搊z), finely chopped
3 tbsp elderflower cordial
1 medium鈥搇arge red onion (approx 150g/5陆oz), sliced into very thin rounds
1 tsp wholegrain mustard
3 tbsp extra virgin olive oil, plus extra to taste
3 tbsp red wine vinegar
120驳/4录辞锄 feta (optional)