Combine lime juice, agave, and jalapeño in a shaker along with ice and shake well.
Pour over a tajin rimmed glass filled with ice. Top with topo chico to flavor.
Garnish with a jalapeño slice or two and/or a lime wedge.
Play around with the proportions on this one- you can make it as sweet or tart as you like and kick up the spice!Enjoy, y'all!