Preheat your oven to 425 degrees Fahrenheit. Add a little flour to a clean surface, then roll out the pie crust to make it big enough to fit into a 9-inch pie dish. Leave about a half inch border of crust beyond the edge of the pie dish, then flute the edges with your fingers. Prick the bottom of the pie crust with a fork several times. Refrigerate the pie dish and crust until your oven is ready.
Cover the pie crust with a sheet of foil then fill it with something heavy to keep the crust from puffing up (raw rice or beans works well, or pie weights if you have them). Bake for 20-25 minutes, until the pie crust edges are golden brown. Take the foil and pie weights out of the pie dish and bake for an additional 5 minutes, until the bottom of the crust is golden brown. Put the pie dish onto a cooling rack for at least 30 minutes.
Meanwhile, add the flour, kosher salt and 1/3 cup of water into a bowl and mix together until smooth.
In a large saucepan, add 2/3 cup of water, 1 cup blueberries and sugar, and bring to a boil. Add the flour mixture, stir well. Bring the blueberry mixture to a boil, making sure to stir constantly for about 5 minutes until it has thickened. Add the lemon zest, vinegar, and the rest of blueberries, stir to combine, then pour the entire mixture into the pie crust.
Refrigerate the pie for at least 3 hours, or until the filling is set. Optional: serve with vanilla ice cream for the perfect treat!