Moisten the rim of each glass and dip into the lemon-lime spicy salt.
Chop the jalapeno into small pieces. Place 1 tbsp -- or more, if you like it spicy -- in each glass.
Fill the shaker halfway with ice, then pour in the watermelon beverage. Add the vodka. Shake until blended.
Fill each glass 1/2 - 2/3 full of ice. Pour shaker ingredients over ice.
Splash a few tablespoons or lemon-lime soda onto the top of each drink. Gently stir.
Enjoy!