Salt the rims of 2 large margarita glasses. To do so, pour salt onto a small plate, moisten the rims of the glasses on a damp towel and press them into the salt.
In a cocktail mixer 3/4 full of ice, combine tequila, Grand Marnier, cointreau, simple syrup, raspberry liqueur and lime juice. Pour in sweet and sour until ice is covered. Shake vigorously and strain into glass.