Preheat oven to 350°F (175°C) and line an 8x8 inch baking pan with parchment paper.
In a large bowl, combine rolled oats, whole wheat flour, sea salt, melted coconut oil, 1/2 cup maple syrup, and vanilla extract until a crumbly dough forms.
Reserve 3/4 cup of the oat mixture for the topping.
Press the remaining oat mixture firmly into the bottom of the prepared pan to create an even base layer.
In a separate mixing bowl, toss blueberries with lemon juice, 1 tbsp maple syrup, and cornstarch until evenly coated.
Spread the blueberry mixture evenly over the pressed crust.
Sprinkle the reserved oat crumble over the top of the blueberries.
Bake for 35 minutes or until the top is golden brown and the blueberry filling is bubbling.
Allow the bars to cool completely in the pan before slicing into 12 equal squares.