Place the margarita mix, tequila, cranberry sauce, triple sec, and lime juice in a blender.
Add 3-4 cups of ice and process until smooth and creamy.
Combine the salt and sugar and spread out evenly in a flat saucer.
Use the lime you have juiced to rub the rims of the glasses to wet them.
Dip the rim of the glasses into the salt and sugar mixture and then pour in the margarita mixture. Serve immediately.
Optional: garnish with small skewers of fresh cranberries.
A regular blender works best with this recipe instead of a Vitamix or Blendtec because those machines are so powerful they can melt your ice if you aren't careful. Keep all of your ingredients, including the tequila and triple sec, in the freezer so they will be icy cold when you start. However, your triple sec will have to be at least 60 proof to leave it in the freezer. Any less, and it will freeze.