Moisten the rim of your margarita glass with a lime wedge and then dip the rim into a dish of salt. Pop the glass into the freezer to chill.
In a cocktail shaker with ice, combine the tequila, triple sec, freshly squeezed lime juice, and passion fruit juice.
Shake vigorously for about 15 seconds until well chilled. Strain the mix into your prepared margarita glass and serve. Garnish with a lime wedge, if desired.