Salmon in a Skillet with Sun-Dried Tomato Couscous and Fennel

One-Skillet Salmon with Fennel & Sun-Dried Tomato Couscous
Ingredients
1 lemon
1 ¼ pounds salmon (see Tip), skinned and cut into 4 portions
¼ teaspoon salt
¼ teaspoon ground pepper
4 tablespoons sun-dried tomato pesto, divided
2 tablespoons extra-virgin olive oil, divided
2 medium fennel bulbs, cut into 1/2-inch wedges; fronds reserved
1 cup Israeli couscous, preferably whole-wheat
3 scallions, sliced