Before squeezing juice from the lemons, roll them on the countertop, applying gentle pressure with the heel of your palm. This will really get the lemons' juices flowing and make it easier to squeeze them.
Puree strawberries and 2 teaspoons sugar in a blender. Set out two glasses, and spoon 3 tablespoons of the resulting strawberry puree, 4 tablespoons sugar, and 4 tablespoons lemon juice into each glass. Stir the lemonade, and add ice. Top off the glasses with seltzer water. Add more sugar if desired.