Place all of the filling ingredients in a food processor or blender, and process until smooth and creamy. Taste and adjust the flavor as needed (see notes).
Set the filling in the fridge while you make the crust.
To make the crust:
Place the chopped dates in a small bowl. To soften the dates, add a tablespoon of water and microwave on high for 30 seconds. (Or soften with a small amount of boiling water. )
Place all of the crust ingredients EXCEPT THE DATES in a food processor. Pulse the dry ingredients on high until finely ground. Then, add the dates a few at a time letting each batch blend in with the dry ingredients. Repeat until all of the dates have been added, and process into a moist but still crumbly dough. Don't over process, or the crust will be tough.
To assemble your mini tarts
Line a muffin pan with paper cupcake liners.
Use a soup spoon to scoop some of the dough into each cupcake liner. Don't press until you have all of the dough evenly distributed throughout the muffin pan.
Use a spoon or a shot glass to press the dough down into the bottom of each cup to form the crust. The dough will be a little sticky, so you'll want to moisten your spoon or shot glass and press down in a rotating motion to keep things from sticking.
When you're done with the crust, place a large spoonful of filling into each cupcake liner, again making sure you have the filling evenly distributed before you smooth out each top.
If desired, sprinkle a little lime zest and coconut on the top of each tart.
Freeze for at least 2 hours. Let sit our at room temperature to soften for 10-15 minutes before serving.
For a lower fat version, you can substitute some extra firm silken tofu for some of the avocado. You may need to add more lime and maple syrup if you want to completely mask the tofu.
It's not always easy to find key limes, so I chose to use regular limes for this recipe. If you plan to use key limes, you'll probably need quite a few (as many as 16 or more) to get 1/2 cup of juice.
When blending the filling, taste it and adjust to your desired sourness/sweetness level, and to make sure the flavor registers as lime to you rather than avocado. Our tolerance for sweet/sour can vary greatly among individuals!