Smoked Salmon and Waffles

Name: Smoked Salmon and Waffles
Ingredients: 1/4 cup sour cream; 1/2 teaspoon lemon zest, plus 1 teaspoon lemon juice; Pinch of kosher salt; 1 1/2 cups all-purpose flour; 1/2 cup whole-wheat flour; 1 tablespoon baking powder; 1/2 teaspoon kosher salt; 2 large eggs, at room temperature; 1 1/2 cups whole milk, at room temperature; 1/4 cup sour cream, plus more for serving; 1 stick (1/2 cup) unsalted butter, melted; 1/4 cup capers, drained and rinsed; 3 tablespoons chopped fresh chives, plus more for garnish; 4 ounces thinly sliced smoked salmon