2 cups fresh lemon juice (from about 10 large lemons)
1/4 teaspoon salt
Make the lemon syrup: Bring the lemon zest, 1 1/2 cups sugar and 1 1/2 cups water to a boil in a medium saucepan, stirring, until the sugar dissolves; let cool to room temperature.
Meanwhile, make the strawberry syrup: Toss the strawberries and the remaining 1/2 cup sugar in a bowl and let sit at room temperature until the sugar dissolves, about 45 minutes. Strain the strawberry mixture; reserve the strawberry syrup and berries separately.
Make the lemonade: Combine the lemon juice, lemon syrup, salt and 2 cups cold water in a pitcher. For each drink, put about 1 tablespoon of the strawberry syrup in a tall glass. Fill with ice, then top with the lemonade and some of the reserved strawberries.