On a small plate, add equal parts chili powder and salt. Swirl to combine. Grab a lowball glass (or small drinking glass). Cut a lime in half. Take one of the lime halves and run along the edge of the glass. Dip the rim of the glass in the chili/salt mixture.
Add the mango and ice to a blender. Blend until combined.
Add the tequila, Triple Sec, and lime juice to the blender and blend until smooth.
Pour into the glass and garnish with a lime slice.
Notes
If you don't have Triple Sec, you can substitute out a different orange liquor.
To make it a mocktail, you can substitute orange juice for the Triple Sec and water for the tequila.