In a ziplock bag, add the corn flakes, and using either a rolling pin or your hands, crush the corn flakes until they are half crumbs and half flakes.
If the peanut butter is not runny, transfer to a microwave safe bowl and microwave for 30 seconds. In a large bowl, combine the maple syrup and peanut butter with a whisk. Pour in the cornflakes, and using a spatula, fold until completely combined.
Line a 9x9 pan with parchment paper or a reusable liner. Transfer the peanut butter cornflake mixture to the pan, and using the bottom of a mug or measuring cup, make sure to press down cornflake mixture until it is firmly on the bottom of the pan.
Melt the dark chocolate chips in a measuring cup or microwave safe container, microwaving 20 seconds at a time until drippy. Alternatively, use a double broiler to melt the chocolate until smooth. Pour on the top of the cornflake mixture, and spread out using a spatula in an even layer on the bars. Finish with sea salt to your liking.
Place in the refrigerator. Remove one hour later and slice into bars. Store in a sealed container in the fridge for up to 3 days.