OPTIONAL: To make sugared cranberries, toss a handful of fresh cranberries in simple syrup, then into dry cane sugar. Once coated in sugar, leave out to dry OR place in the oven at its lowest temperature setting to dry faster.
Squeeze lime juice using a citrus juicer.
On the rim of the glasses you're using, rub them with a lime wedge. Then, pour some kosher salt onto a small plate. Tap the rubbed rim of the glass on the salt until coated.
Measure remaining ingredients and pick mint leaves.
To a cocktail shaker, add a handful of ice cubes, then add the lime juice, tequila, cranberry juice, cointreau, simple syrup, and a few fresh mint leaves.
Close the lid on the shaker tightly, then shake vigorously for at least 30 seconds to 1 minute.
Add a few ice cubes to each rimmed glass.
Then, strain the cocktail evenly into three glasses.
If there's extra room in the glasses, try topping it off with seltzer water or champagne.
Garnish each glass with a fresh mint spring and a few sugared cranberries.
Serve cold and enjoy!