Stir 1/2 cup water and sugar in heavy medium saucepan over medium heat until sugar dissolves and syrup comes to boil. Add cherries. Remove mixture from heat; cool 30 minutes. Mix in kirsch. Cover and refrigerate 1 day.
Using electric mixer, beat butter in large bowl until fluffy. Add sugar and beat until smooth. Beat in egg and vanilla. Sift flour, cocoa, and salt over; beat to blend. Using moistened fingertips, press dough over bottom and up sides of 11-inch-diameter tart pan with removable bottom. Cover and chill at least 1 hour and up to 1 day.
Preheat oven to 350°F (180°C). Drain cherries, reserving cherry syrup. Sprinkle cherries in crust. Combine eggs, corn syrup, butter, vanilla, and salt in large bowl. Add sugar and 1/4 cup cherry syrup; beat to blend. Mix in chocolate. Pour filling into crust.
Bake tart until set in center, about 1 hour. Cool on rack 30 minutes. (Can be made 1 day ahead. Cover; store at room temperature.) Release tart from pan. Dust with confectioners' sugar and cocoa. Serve warm or at room temperature.
Makes 10 to 12 servings.
Source: Bon Appétit Magazine September 2002
Date: August 13, 2004