Preheat your oven to 350°F (175°C). In a mixing bowl, combine graham cracker crumbs and unsweetened shredded coconut. Pour in the melted unsalted butter, mixing it all together until fully combined. Firmly press the mixture into an 8x8 inch baking dish, ensuring the base is even and compact. Bake for 10 minutes or until golden brown, then remove from the oven and allow the crust to cool completely.

In a large bowl, whisk together the sweetened condensed milk, coconut milk, lime zest, lime juice, granulated sugar, and a pinch of salt until the mixture is smooth and well blended. Set this filling aside while you whip the cream.

In a separate chilled bowl, pour in the heavy whipping cream. Using an electric mixer, beat the cream on medium-high speed until you achieve stiff peaks, about 2-4 minutes. Once whipped, gently fold the whipped cream into the coconut lime mixture until just combined.

Carefully pour the creamy coconut lime filling over the cooled crust, using a spatula to smooth the top. Cover the baking dish tightly with plastic wrap and place it in the freezer. Allow it to freeze for at least 4 hours or until the filling is set.

To serve, remove the bars from the freezer and let them soften at room temperature for 5-10 minutes. Garnish with lime slices and toasted coconut if desired.