Add entire can of coconut milk to blender and mix until completely combined. Coconut milk will often congeal and separate into liquid and solid in the can. This step ensures even consistency.
Measure out 2/3 cup coconut milk for the mocktails. Save extra coconut milk for your morning coffee or for another batch of mocktails later.
Blend coconut milk, lime juice and lime sparkling water in a blender until completely combined.
Add ice cubes and shake to chill.
Edge martini glasses with the juice of sliced lime and press glass into a plate of coconut flakes to decorate rim if desired.
Split the mocktail evenly among 4 glasses and enjoy.