Run a lime wedge around the rim of a Martini glass. Dip each moistened rim in the salt, and set aside.

Use the rest of the juice from the lemon to put in a shaker. Add ice cubes, tequila, orange liqueur (Cointreau!!!) and shake till you drop.

Crunch some ice and put it in the Martini glass. Put the mixture in the glass.

Garnish the glass with a (half) slice of lemon.