Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. Peel and mince or grate ginger until you have 2 TBSP. (TIP: Save any extra ginger for another time. We like throwing whole knobs into our tea.) Trim and finely chop scallions. Quarter lime. Trim and halve Brussels sprouts.

Toss Brussels sprouts on a baking sheet with a large drizzle of oil and a large pinch of salt and pepper. Roast on top rack for 15 minutes, then remove from oven and carefully toss with 2 tsp soy sauce (save the rest for step 6). Return Brussels sprouts to oven until browned and crispy, about 5 minutes more.

Meanwhile, melt 1 TBSP butter in a small, lidded pot over medium-high heat. Add 1 TBSP minced ginger. Cook, stirring, until fragrant, about 1 minute. Add 3/4 cup water and a pinch of salt, then bring to a boil. Stir in rice, then cover and reduce heat to low. Cook until water has absorbed and rice is tender, about 15 minutes.

Meanwhile, in a medium bowl, combine scallions, sesame oil, 1 tsp minced ginger, 1 tsp sugar, juice from 2 lime wedges, and as much sriracha as you like. Season with salt and pepper. Taste and add more ginger or lime juice, if desired.

Pat barramundi dry with paper towels; season all over with salt and pepper. Heat 1 TBSP oil in a large pan over medium-high heat (use a nonstick pan if you have one). Add fish, skin sides down, and cook until lightly browned and crispy, 3-4 minutes. Carefully flip and cook until fish is firm and cooked through, 3-4 minutes more.

Fluff rice with a fork, then stir in 1 TBSP butter until melted. Season with salt and pepper. Divide rice and Brussels sprouts between plates. Top with fish and pesto. Drizzle with remaining soy sauce (to taste). Serve with any remaining lime wedges on the side.