Place limeade and tofu in a blender; process until smooth. Add 1 1/2 cups water; pulse to combine. Pour mixture into the freezer can of an ice-cream freezer; freeze according to manufacturer's instructions. Spoon the mixture into a freezer-safe container; cover and freeze 2 hours or until firm. Garnish with mint and rind, if desired.
Making homemade ice cream, sorbets, and other frozen treats like this one at home is easy. You've got a couple of options when it comes to ice-cream makers: an old-fashioned bucket churn or a countertop freezer. Traditional bucket-style freezers require rock salt and ice, but tabletop models rely strictly on a freezer bowl filled with coolant.