In a small saucepan over medium heat, combine blueberries, balsamic vinegar, honey, Dijon mustard, and lemon zest. Stir for 5-6 minutes until the blueberries burst and the glaze thickens. Remove from heat and let cool slightly.

Preheat the oven to 400°F (200°C). Prepare a baking sheet lined with aluminum foil. Place salmon fillets on the sheet, drizzle with olive oil, and season with salt and black pepper. Brush blueberry glaze over each fillet and bake for 12-14 minutes until cooked through.

While the salmon bakes, in a medium bowl, combine dry couscous with a pinch of salt. Pour boiling water or broth over it, cover, and let sit for 5 minutes. Fluff with a fork and mix in lemon juice, lemon zest, olive oil, and chopped herbs.

To serve, place a scoop of couscous on each plate, top with salmon fillets, and drizzle with any remaining glaze. Garnish with fresh herbs or lemon wedges.