Place squash halves cut side down on a cutting board. Slice into ½-inch slices. Transfer slices to a bowl. Drizzle with olive oil; add salt and cayenne pepper. Toss to coat squash with oil.
Preheat oven to 450°F. Line a rimmed baking sheet with parchment paper or a silicone mat.
Arrange squash pieces in a single layer on prepared baking sheet. Place in preheated oven until bottom of slices are browned and squash is tender, 12-18 minutes.