Fold a 30- x 18-inch piece of parchment paper in half lengthwise; fold in half again crosswise (short end to short end) to create a 4 layer thick piece. Place folded parchment in bottom of a 6-quart slow cooker, letting ends extend partially up sides.

Place half of lemongrass, fennel, and scallions in an even layer on parchment in slow cooker. Add water and wine. Sprinkle salmon with 1 teaspoon salt and 1/2 teaspoon pepper; place on lemongrass mixture. Top salmon with remaining lemongrass, scallions, and fennel. Cover and cook on HIGH until salmon flakes easily with a fork, 1 to 2 hours. Using parchment paper liner as handles, lift salmon from slow cooker, allowing liquid to drain off. Discard mixture in slow cooker. Set salmon aside.

Preheat oven to 425°F. Toss Brussels sprouts with 1 tablespoon olive oil, 1 teaspoon kosher salt, and 1/2 teaspoon black pepper on a rimmed baking sheet. Bake in preheated oven until tender and starting to crisp, 20 to 25 minutes. Heat remaining 1 tablespoon olive oil in a skillet over medium-high and cook mushrooms and remaining 1/2 teaspoon kosher salt until tender, 3 to 4 minutes. Add mushrooms to baking sheet with Brussels sprouts; wipe skillet clean.

Cook pineapple juice, soy sauce, brown sugar, and cornstarch in skillet over medium, whisking constantly, until thickened, about 3 minutes. Brush 1/4 cup sauce on about 1 1/4 pounds cooked salmon; sprinkle with sesame seeds.

Place salmon on baking sheet with mushrooms and Brussels sprouts; broil on HIGH 6 inches from heat until glaze has thickened, about 2 minutes.

Divide brown rice among 4 bowls. Top evenly with salmon, Brussels sprouts, mushrooms, and matchstick carrots. Drizzle with remaining sauce; serve with lime wedges.