In a small bowl, stir together salt and chili pepper for the rim. Pour out onto a small plate. Rub the rims of 2 cocktail glasses with a wedge of lime. Roll the wet rim in the chili salt mixture. Fill glasses with ice and set aside.
Add all ingredients for the margarita in a shaker filled with ice. Shake well.
Strain the cocktail into both glasses, dividing evenly between the two.
Garnish with blood orange slices and serve.