In a small bowl, combine 2 tablespoons sea salt with 1 tablespoon Tajín. Stir until well distributed. Pour some of the chili salt on a plate. Rub a lime wedge around the edge of a rocks glass or margarita glass. Roll the rim of the glass in the chili salt to coat the rim.
In a cocktail shaker filled with ice, add tequila, triple sec, blood orange juice and agave nectar. Shake well.
Add ice to the prepared rocks glass. Strain the cocktail into the glass. Top with orange bitters.
Garnish with slices of lime and blood orange.
Notes
Want something sweeter? Rim your glass with sugar instead of salt and chili-lime seasoning.For a non-alcoholic margarita: Use a zero-proof spirit to replace the tequila and a splash of orange juice instead of triple sec.