Preheat the oven to 350 degrees F (175 degrees C).
Combine sugar, lemon juice, eggs, flour, and lemon zest for filling together in a large mixing bowl, and whisk until well blended. Set aside.
Combine flour, butter, sugar, and salt for crust in the bowl of a food processor and pulse several times, until the dough begins to come together in a ball.
Divide the dough into 6 equal portions, placing dough portions in each well of a nonstick 6-well mini tart pan. Press dough over the bottom of each well and up the sides.
Bake in the preheated oven until the filling is set and the crust is lightly browned, 25 to 30 minutes. Cool on a wire rack until mini tarts reach room temperature.