Puree the cucumbers, jalapeños, sugar and ? cup water in a blender until smooth. Strain through a fine-mesh sieve into a large pitcher. Add 1 cup lime juice to the pitcher and stir. Refrigerate until ready to serve.
Pour the remaining 2 tablespoons lime juice on a plate. Combine 2 tablespoons salt and the chile powder on another plate. Dip the rims of 8 glasses into the lime juice, then into the salt mixture. Add ice to the glasses.
Add the soda to the pitcher and stir, then divide the punch among the glasses. Garnish with gummy candies.
For a grown-up punch, use gin instead of soda. Finish with just a splash of soda to sweeten.