In your blender, combine ice, Sprite, tequila, blue curacao, and limeade. Blend. If needed, add ice to get a thicker consistency, or add extra Sprite for a thinner consistency. It’s easier if they are pourable, but if you want a more slushy margarita, you can make it thicker. To serve, add a layer of coarse sugar to a small saucer.
Run a slice of lime along the rim of your glasses, and then dip the glasses into the sugar. Garnish with fresh lime slices.