Prepare your lime slice. Cut a slice from the center of your lime, and then cut a slit in the side that we'll use to attach it to the glass rim later. Set aside.
Add the lime juice, coconut milk and simple syrup to a cocktail shaker.
Fill the shaker with ice.
Shake the drink vigorously about 10-15 times to chill the liquid.
Strain the drink into your serving glass.
Top it off with the lime seltzer.
Attach the lime slice to the rim of the glass before serving. Cheers!