Make the Syrup
In a large jar with a tight-fitting lid, vigorously shake sugar, jalapenos and water until the sugar dissolves, about 1 minute. Strain into a pitcher.
Mix the Drink
In a food processor, puree cucumbers; strain. Add cucumber juice (about 2 cups), tequila, orange liqueur and 1 cup lime juice to the pitcher; stir.
Rim the Glass
Pour 2 tbsp. lime juice on a plate. Spread salt and chili powder on another plate. Dip the rims of 8 glasses into the lime juice, then into the salt and chili powder
Fill the glasses with ice, then add the margarita. Garnish with cucumber ribbons.