Pre-heat oven to 375°F.
Place chopped rhubarb, in a medium bowl, and completely cover with hot water; let sit for 5 minutes; drain.
Pour rhubarb in the pie crust.
Sprinkle flour over the top; set aside.
In a large bowl, mix together the milk, eggs, sugar, vanilla and salt.
Pour mixture over rhubarb.
Place pie in the pre-heated oven and bake for 15 minutes.
Reduce temperature to 350°F and bake for an additional 30 to 45 minutes or until the custard is firm.
Remove from oven and place on a wire rack to cool.