Salmon with Potatoes and Horseradish Sauce

3 tablespoons canola oil, divided

1 pound baby red potatoes, cut into 1/4-in.-thick slices
1/2 cup water
1 teaspoon kosher salt, divided
3/4 teaspoon black pepper, divided
4 (6-oz.) skin-on salmon fillets (1 in. thick)
1/2 cup light sour cream
2 tablespoons chopped fresh dill
1 tablespoon creamy prepared horseradish

 Heat 1 1/2 tablespoons oil in a large nonstick skillet over medium-high. Add potatoes; cook 8 minutes or until golden, stirring occasionally. Add 1/2 cup water; bring to a boil. Reduce heat and simmer, partially covered, 8 minutes or until potatoes are tender. Sprinkle with 1/2 teaspoon salt and 1/2 teaspoon pepper.

Meanwhile, heat the remaining 1 1/2 tablespoons oil in a large skillet over high. Sprinkle salmon with the remaining 1/2 teaspoon salt and the remaining 1/4 teaspoon pepper. Add salmon to pan; cook 4 minutes on each side or until the desired degree of doneness.

Combine sour cream, dill, and horseradish in a bowl. Serve with salmon and potatoes.