2 tsp olive oilfinely grated zest and juice of 2 lemons
For the watercress salad
85g bag watercress
½ red onion, peeled, thinly sliced
1 tbsp salt
400g can chickpeas, drained
salt and black pepper
Method
Place the tuna on a plate, mix together the lemon juice, pepper and oil and pour over the fish. Cover and marinate in the fridge for 30 mins, turning once.
To make the salsa verde, place all the ingredients in a food processor with 2 tbsp of cold water and blend to form a smooth paste. Season with salt and pepper to taste.
Heat a large griddle pan and cook the tuna for 5-6 mins, turning once until chargrilled but still a little pink in the middle. Serve with the salsa and salad.