Preheat the oven to 350°F and grease a 12-cup mini muffin tin.
Make the crust: Pulse all coconut crust ingredients in a food processor until a dough forms. If the mixture is still crumbly, add 1 tablespoon of cold water and pulse again.
Press and bake crust: Divide the dough evenly into the 12 muffin cups and press it firmly into the bottoms and slightly up the sides. Bake for 10–12 minutes until just set, then remove from the oven.
Make the filling: In a mixing bowl, stir together the maple syrup, coconut sugar, melted coconut oil or vegan butter, arrowroot or cornstarch, vanilla, sea salt, and eggs or flax eggs until smooth. Fold in the pecan halves.
Fill and bake: Spoon the pecan filling into the pre-baked crusts, dividing evenly. Bake for 25–30 minutes, until the tops are golden and puffed and the centers are mostly set.
Cool fully in the pan before removing the tartlets. Finish with a sprinkle of flaky salt if desired.