For the crust: combine dates, walnuts, pecans, oil, and syrup in a food processor and pulse until everything is mixed together. You may want to do this in 2 batches.
Grease a muffin tin with coconut oil then evenly distribute the crust, using your hands or a spoon to smash it down flat; place tin in the freezer.
For the filling: place cashews, milk, oil, syrup, extract, and lime juice in a high-power blender and pulse. If mixture seems to be stuck, add additional milk 1 tbsp at a time, but be careful not to add too much additional milk or the filling will be too thin.
Pour cashew cream overtop of the 12 tart crusts, evenly distributing it.
Sprinkle each tart with lime zest and place muffin tin back in the freezer for at least 20 minutes, allowing time for them to harden.
Store tarts in the freezer and use a knife to remove tarts from muffin tin.
Eat frozen OR leave out for 10 or so minutes, allowing time for them to thaw before eating.