Preheat a grill or grill pan over medium heat and brush the grates lightly with coconut oil.
Place the banana halves cut-side down on the grill and cook for 2 to 3 minutes per side, until lightly charred and warmed through.
Meanwhile, make the sauce by combining the coconut milk, brown sugar, butter, salt, and cinnamon in a small saucepan over medium heat.
Simmer gently, stirring often, for 4 to 6 minutes until slightly thickened and glossy.
Remove from the heat and stir in the vanilla extract.
Serve the grilled bananas warm, drizzled generously with the coconut caramel sauce.