Heat 1 teaspoon of oil in a large nonstick skillet over medium heat. Add onion, bell pepper, corn, and 1 teaspoon of Cajun seasoning, and cook, stirring, until the vegetables are softened, about 4 minutes. Transfer to a large bowl. Let cool for 5 minutes. Add the crab, egg white, 1/2 cup of breadcrumbs, mayonnaise, and lemon zest. Mix well.