Heat the oven to 400°F and coat a 9-by-13-inch baking dish with cooking spray.
Stir the basmati rice, broth, lemon juice, dill and 1/2 teaspoon salt together in the dish, then cover tightly with foil.
Bake for 25 minutes without lifting the foil.
Uncover, stir the peas into the rice, set the salmon pieces on top and season them with the remaining salt and black pepper.
Reseal the foil and bake for 15 to 18 minutes, until the salmon reaches 145°F and the rice has no hard center.
Add 2 tablespoons hot broth and bake covered for 5 minutes more if the rice is firm, then rest for 5 minutes.