Drain 1 (#2) can sour pie cherries. To juice add 3/4 cup sugar and 4 level tablespoons of cornstarch. Blend smooth and cook until thick and clear, stirring constantly. Add cherries, dash of salt, and 2 teaspoons fresh lemon juice. Mix and pour into crust. Top with crumbs and bake at 375 degrees until bubbly. Serve cool, with vanilla ice cream, whipped cream, or plain.