Mix flour and salt in processor. Add butter and cut in, using off/on turns, until mixture resembles coarse meal. Add sugar and egg yolks and process briefly to blend. Add 2 tablespoons water and process just until moist clumps form. If dough is dry, add more water by teaspoonfuls to moisten. Gather dough into ball; flatten into disk. Wrap in plastic and refrigerate until dough is firm enough to roll, about 30 minutes.
Preheat oven to 350°F. Roll out dough disk on floured surface 12-inch round. Transfer to 9-inch-diameter tart pan with removable bottom. Trim crust overhang to 1/4 inch. Fold overhang in, creating double-thick sides. Freeze tart crust 15 minutes.
Line crust with foil. Fill with dried beans or pie weights. Bake until sides are set, about 20 minutes. Remove foil and beans. Bake until crust is golden brown, piercing with fork if bubbles form, about 15 minutes. Brush crust with jam and bake until jam is set, about 5 minutes more. Transfer pan to rack and cool.
Combine sugar and water in heavy large skillet over low heat. Stir until sugar dissolves. Add lemon peel and cinnamon stick. Increase heat and bring to boil. Add rhubarb and bring to boil. Reduce heat to medium-low. Cover pan and simmer until rhubarb is just beginning to soften, about 5 minutes. Remove pan from heat. Let stand covered until rhubarb is tender, about 15 minutes. Uncover and cool completely.
Using slotted spoon, remove rhubarb from cooking liquid and arrange in concentric circles in crust. Strain cooking liquid into heavy small saucepan. Boil liquid until reduced to 1/4 cup, about 5 minutes. Cool syrup completely. Spoon syrup over rhubarb.
Bon Appetit May 1996