1-2fresh jalapeno slicesseeds removed for less spice
On a small plate, combine kosher salt and chili powder (or tajin) until mixed. Rub half of a lime on the rim of your serving glass and dip into spice mix. Set aside.
In a cocktail shaker, jar, or glass if you don't have either, muddle together mango, lime juice, and jalapeno. Add 3-4 ice cubes and pour in the tequila. Add mango juice and shake (or stir if you don't have a lid). Add fresh ice to serving glass; strain the cocktail over the fresh ice. Top with jalapeno or mango and garnish as desired.
Adjust tequila and juice ratio for the desired strength of alcohol.