Preheat oven to 425°F. Combine apples, oil, cinnamon, and 1/4 teaspoon of the salt on a half-size (18- x 13- x 1-inch) rimmed baking sheet; toss to coat. Bake in preheated oven until apples are tender and beginning to brown, 15 to 20 minutes, stirring after 10 minutes.