Seared Salmon with Israeli Couscous

Name: Seared Salmon with Israeli Couscous
Ingredients: 1 cup whole-wheat Israeli couscous; 1 Gala apple, chopped; 1 cup fresh flat-leaf parsley leaves and tender stems; 1 cup baby arugula; 1 small red onion, thinly sliced; ¼ cup toasted pine nuts; 3 tablespoons plus 2 teaspoons olive oil, divided; 1 tablespoon whole-grain mustard; 1 tablespoon lemon zest plus 2 Tbsp. fresh juice (from 2 lemons), plus wedges for serving; ¾ teaspoon kosher salt, divided, plus more for cooking couscous; ¾ teaspoon freshly ground black pepper, divided; 4 6-oz. skin-on salmon fillets