(Optional step) -- If you would like to make the rim of each glass to look like a margarita's, place 2-3 drops of green food coloring into a gallon ziploc bag. Zip and smash to distribute the coloring. Spoon about 1/4 cup granulated, zip the bag, and mix the sugar and food coloring together until homogeneous. Place into a small bowl and let dry for at least 5-10 minutes.
Meanwhile, combine the lime juice with tequila in a medium bowl. If you would like to place colored sugar around the rim of the glasses, invert glasses onto the lime juice/tequila mixture and then, onto the bowl with the colored sugar. Set aside.
Then, wet (not soak) the ladyfingers into the lime juice/tequila mixture one by one on both sides. Distribute them into 3 glasses (If necessary, cut a piece of each cookie with a serrate knife before wettening them in order to fit the glass).
In a large bowl, whisk the the mascarpone cheese with sugar and coconut milk until obtaining a creamy mixture. Stir in the coconut flakes and fold the whipped cream gently until obtaining a homogeneous, creamy mixture. Spoon or pipe into the glasses.
Refrigerate for at least 2 hours or until chilled. Right before serving, sprinkle lime zest on top of each and enjoy our coconut lime margarita tiramisu!