Heat the oil in a large skillet over medium heat.
Season the salmon with ½ teaspoon salt and ¼ teaspoon pepper. Cook until opaque throughout, 5 to 6 minutes per side.
Meanwhile, in a large saucepan fitted with a steamer basket, bring 1 inch of water to a boil. Place the beans in the basket, cover, and steam until tender, 4 to 5 minutes.
In a small bowl, combine the sour cream, lemon juice, dill, capers, and ¼ teaspoon each salt and pepper. Serve with the salmon and green beans.