Start by preparing your margarita glasses. Pour some of the Tajin onto a small plate.

Run the lime wedge gently around the rim of each glass. Run the rim through the Tajin until it's thick enough for your taste. Fill the glass with ice.

Strain the watermelon puree to remove any pulp or seeds.

Add watermelon puree, tequila, triple sec, lime juice, and a few slices of jalapeño to a cocktail shaker with ice.

Shake the cocktail shaker for 30 seconds to chill the mixture., Then strain the mixture into the Tajin-rimmed glass filled with ice. Garnish with a slice of watermelon or a wedge of lime, and enjoy!