Pour salt over a small plate; rub the lime wedge over the rim of each glass. Dip each glass into the salt and set aside. (Or transfer to the refrigerator to chill.)
Blend the Tequila, Triple Sec (or Cointreau), lime juice, simple syrup (if using) and ice together until ice is crushed and the consistency of a slushy. Add more ice as needed. Serve immediately.
Notes
Tip: If the slushy is too strong for your tastes, add 1/4 cup lemonade to dilute the alcohol and add some sweetness!