Preheat oven to 325ºF. Spread sunflower seeds in an even layer on baking sheet and roast for 10 minutes.
Increase oven temperature to 350ºF. Grease 9-inch square baking pan with coconut oil or non-stick spray.
Combine sunflower seeds, 3 cups rolled oats and sea salt in a food processor or blender. Process until coarse flour forms.
In a small pot, melt 1/2 cup coconut oil over low-medium heat. Remove from heat and stir in maple syrup and sunflower butter until well combined. Add oil to oat flour and process for another 15-20 seconds until dough forms (you may need to scrape down the sides of the blender once or twice to make sure everything is well combined).
Pour dough into prepared pan and press down firmly into an even layer. Bake for 10-12 minutes until firm to the touch. Let cool for 5 minutes.
While crust is baking, melt 2 tbsp coconut oil in a small pot. Stir in remaining 1/3 cup rolled oats until well coated.
Spread an even layer of jam over cooled crust, then top evenly with oat crumble. Bake for an additional 15-18 minutes until edges start to brown slightly.
Once cool, cut the oatmeal bars into squares.
Store in airtight container in the fridge for up to 1 week or freeze for 4-5 weeks.