In a large bowl, toss the strawberries with the sugar and salt to coat, then let sit at room temperature for 12 hours.
Strain out the fruit and transfer the liquid to a medium saucepan with the remaining ingredients over high heat. Cook until the liquid reads 220º on a candy thermometer, 5 to 6 minutes, then pour over the fruit and let sit for another 12 hours.
Repeat this process of straining the fruit, boiling the liquid and pouring the hot liquid over the fruit 3 more times, each time raising the temperature by 2º.
Divide the cooled fruit and liquid between the 2 mason jars, pressing the strawberries down until there is only about ½ inch of space left at the top of each jar. Wipe the rim then affix the lid on each jar.
Bring a stockpot filled with water to a boil. Make sure there is enough water for the jars to be completely submerged. Arrange the jars on a wire rack and lower into the water. Process the jars in boiling water for about 15 minutes.
Carefully remove the jars and let them cool to room temperature on a folded towel, making sure not to disturb the lids or tops of the jars. Check the seals after 24 hours; they should not flex up and down when pressed in the center. The pickled strawberries will keep for up to 1 year.