1. Combine first 3 ingredients in a medium saucepan over medium-high heat; bring to a boil. Remove from heat; stir in cilantro and jalapeño. Let stand 30 minutes. Pour jalapeño mixture into a large bowl; cover and chill at least 3 hours.
2. Combine 2 tablespoons sugar and salt in a shallow dish. Rub rims of 8 glasses with 1 lime wedge. Dip the rims of glasses in sugar mixture.
3. Strain cilantro mixture through a fine sieve over a bowl, discarding solids. Stir in lime juice. Fill each prepared glass with 1/2 cup ice. Add 3/4 cup limeade to each glass. Garnish with remaining 8 lime wedges.