Instructions:

To make the jalapeno simple syrup, combine water, sugar, and sliced jalapeno pepper in a saucepan over medium heat. Stir until sugar dissolves and mixture comes to a boil. Reduce heat and simmer for 5 minutes. Remove from heat and let cool. Strain out jalapeno slices and transfer syrup to a jar or bottle.

Rim a highball glass with salt by rubbing a wedge of lime around the rim, then dipping the glass in a small dish of salt.

Fill the glass with ice.

In a shaker, combine the tequila, lime juice, watermelon juice, and jalapeno simple syrup.

Shake well to combine and chill.

Strain the mixture into the glass over ice.

Top off the glass with club soda.

Garnish with a lime wedge.