1 Rinse fish and pat dry. Cut out 4 squares of parchment paper (about 40 x 40 cm) (approximately 16 x 16 inches). Place 2 fish fillets side-by-side on each square.
2 Form the parchment squares into packets with an opening at the top. Tie the ends with kitchen twine and place the packets on a baking sheet.
3 Rinse limes in hot water, wipe dry and finely grate the zest. Cut 2 limes into thin slices and squeeze out juice from the 3rd lime into a small bowl.
4 Add the lime zest, chili sauce and soy sauce to the lime juice and season with pepper. Coat the fish with the lime zest-sauce mixture and cover with slices of lime. Bake in preheated oven at 180°C (fan 160°C, gas mark 2-3) (approximately 350°F/convection 325°F), on the middle rack, until fish is cooked through, about 15 minutes.
5 Meanwhile, rinse cilantro, shake dry and pluck leaves. Remove packets from the oven, sprinkle cilantro over the fillets and serve immediately.