Add the tequila, Cointreau or triple sec, lime juice, simple syrup (optional), mango chunks, and crushed ice to your blender jar. Blend until you have a slushy consistency.
Serve:
Pour the frozen margarita into a glass. Squeeze about ¼ of the chili paste into the middle of the mango margarita, and using a cocktail spoon, swirl it to mix it into the cocktail. Garnish.