Cook your fish in parchment paper and never look back!
Preheat the oven to 400°. In food processor, pulse citrus zests, chiles, and salt until paste forms. Pulse in citrus juices. With machine running, add oil.
Fold four 15-by-20-inch sheets of parchment paper in half. Draw half of a heart shape along each folded edge. Cut along lines. Open hearts flat on counter. Divide bok choy and bell peppers among hearts; arrange on one side of fold. Drizzle vegetables with 2 tbsp. sauce for each packet; season. Top with fish; season. Drizzle each fillet with 2 tbsp. sauce. Fold paper over. Starting at top of heart, crimp edges in 1-inch sections down toward point of heart; twist point to seal packet.
Place packets on baking sheet. Bake at 400° for 15 minutes.