In a food processor, combine almonds or cashews, shredded coconut, Medjool dates, and melted coconut oil. Pulse until the mixture reaches a clumpy consistency resembling coarse crumbs. Press firmly into the bottom of an 8x8 inch pan lined with parchment paper. Chill in the refrigerator for about 15 minutes.

In a large mixing bowl, whisk together full-fat coconut milk, chia seeds, maple syrup or agave, lime zest, lime juice, vanilla extract, and a pinch of salt until everything is thoroughly combined. Let the mixture sit for 5-10 minutes to thicken.

Once the filling is prepared, pour it over the chilled crust or into the lined pan if making crustless bars. Spread evenly and cover with plastic wrap. Chill for at least 4 hours or overnight.

After chilling, lift the bars out using the parchment paper. Optionally sprinkle toasted coconut flakes and extra lime zest on top. Cut into squares and serve chilled.