In a blender, combine the tequila, triple sec, lime juice, simple syrup, mango chunks and ice. Blend just until smooth and no chunks of ice remain, usually less than 30 seconds.

Pour a few tablespoons of Tajin spice onto a small rim plate. Wet the rim of a glass by rubbing it with a cut wedge of lime, then dip the rim in the Tajin, coating it evenly. Repeat with the remaining glasses, and garnish each one with a slice of lime. Pour the blended margaritas into the prepared glasses and serve. Cheers!