Citrus-seared tuna with crispy noodles, herbs & chilli

INGREDIENTS

• 2 pink grapefruits
• 1 tablespoon fish sauce
• 500 g piece tuna, from
• , ask your fishmonger
• 1 tablespoon sesame oil
• 6 tablespoons olive oil, plus extra for frying
• 2-3 fresh red chillies, very finely sliced
• sea salt
• freshly ground black pepper
• 1 large bunch fresh coriander
• 1 small bunch fresh mint
• 2 good handfuls of glass or cellophane noodles
• 4 spring onions, finely sliced at an angle