For the swordfish: 1) Place a griddle pan over medium-high heat or preheat a barbecue or griddle.
2) Brush both sides of the swordfish fillets with olive oil and season with salt and pepper. Griddle the swordfish about 3 to 4 minutes on each side for a 2.5cm thick fillet.
3) Transfer the grilled swordfish to serving plates, top with the citrus pesto, and serve.
For the citrus pesto: 1) Blend the basil, pine nuts, garlic, zests, juices, salt, and pepper in a food processor until the mixture is finely chopped. With the machine running, gradually add the olive oil until the mixture is smooth and creamy.