Salt the rim of the glass, if desired
Put 4 orange wedges and 2 lime wedges into a metal cocktail shaker. Add the tequila and lime liqueur.
Muddle gently, avoiding the rinds, which can add a bitter taste.
Add a small scoop of ice and the soda water to the shaker. Pour back and forth between the shaker and a large mixing glass a few times.
Pour the margarita into the salted (if using) serving glass. Garnish with a lime wedge.