Preheat oven to 400 degrees. Line a rimmed baking sheet with parchment paper.
Pat rinsed chickpeas with a clean kitchen towel and place in a large bowl. Add olive oil, cajun seasoning and sea salt. Toss to coat and transfer to a prepared baking sheet in a single layer.
Bake for 35 to 45 minutes, stirring half way through. Remove from oven and allow to cool.