Preheat oven to 350 degrees F (180 C) and grease an 8x8 inch pan with a light amount of oil. In a medium mixing bowl, combine chia seeds and coconut milk and set aside for about 10 minutes. Add the melted coconut oil, salt, baking powder, cinnamon, vanilla, and sugar. Mix in the flour just until smooth.
Pour the batter into the prepared pan and smooth with a spatula. In the same bowl (no need to wash) stir together the ingredients until well combined into a crumbly dough. Sprinkle the topping over the pan as evenly as possible. Bake the cake for 40 to 45 minutes until a toothpick inserted in the center comes out clean. Allow the cake to cool for at least 15 minutes before cutting.