Hot Reuben Dip

Name: Hot Reuben Dip
Ingredients: 10 ounces corned beef , from the deli counter or homemade , chopped; 10 ounces cream cheese , room temperature; 6 ounces Swiss cheese slices from the deli counter, cut into small pieces; 3/4 cup sauerkraut , drained; 1/2 cup Thousand Island dressing , homemade or store-bought; 1 teaspoon caraway seeds; 8 slices rye bread , divided; 3 tablespoons butter , plus more for the toast; 1/2 teaspoon kosher salt , plus more for sprinkling; 1/2 tablespoon minced chives , for garnish