For the syrup: In a small saucepan, combine the sugar and water over medium heat. Bring the mixture to a boil, reduce the heat, and simmer until the sugar has dissolved, stirring occasionally, about 5 minutes. Remove the pan from the heat and allow the syrup to cool, about 20 minutes.
For the tea: In a medium saucepan, bring the water to a boil over medium-high heat. Add the tea bags and lemon slices. Let the mixture cool to room temperature, about 1 hour. Remove the tea bags and discard.
Pour the syrup and tea mixture into an ice-filled pitcher. Pour into glasses and add a splash of sparkling water. Garnish with lemon slices and serve.
To dry lemon slices: arrange in a single layer on a wire rack. Place on a baking sheet and bake in a preheated 150 degrees oven for 1 to 1/1/2 hours until dry and crisp. Store in an airtight container at room temperature. Alternatively, the lemon slices can be dried in a dehydrator following the manufacturer's instructions.