1.3 cups juice of lime fresh for serving from 8 to 10 limes
0.5 cup lightly mint leaves packed
0.7 cup liqueur orange-flavored such as Cointreau or Grand Marnier
2 cups strawberries frozen
1 cup sugar
0.8 cup tequila preferably anejo or reposado
Equipment
bowl
baking sheet
blender
plastic wrap
ice cube tray
Directions
Combine 3/4 cup lime juice, 1/3 cup sugar and 3/4 cup water in a bowl; stir until dissolved.
Pour into an ice cube tray and freeze until firm, 1 to 2 hours. Meanwhile, line a baking sheet with plastic wrap; spread out the melon chunks, cover and freeze until solid, 1 to 2 hours. (The lime ice cubes and melon can be frozen up to 2 days ahead.)
Combine the lime ice cubes, tequila, orange-flavored liqueur and 2 cups plain ice cubes in a blender and process until slushy.
Transfer to a small pitcher or bowl; cover with plastic wrap and freeze, about 2 hours. Rinse out the blender.
Combine the frozen strawberries, elderflower liqueur, 1/4 cup lime juice, 1/3 cup sugar and 2 cups plain ice cubes in the blender; process until slushy.
Transfer to another small pitcher or bowl and set aside. Rinse out the blender.
Make the green layer: Blend the frozen melon, mint, the remaining 1/4 cup lime juice and 1/3 cup sugar, 1 1/2 cups plain ice cubes and 1/2 cup water until slushy.
Rub the rims of 6 glasses with a lime wedge, then dip in coarse salt. Fill each glass one-third of the way with the green slush; spoon a layer of the white slush on top, then finish with the red slush.
Serve with lime wedges. (The individual slushes or the assembled drinks will keep up to 3 days in the freezer. Thaw 20 to 40 minutes before assembling or serving.)