In a medium saucepan, stir together the water and cornstarch until dissolved.
Stir in the frozen raspberries, sugar, and salt, then place over medium heat.
Zest 1 of the oranges, and stir the zest into the rest of the ingredients.
Cook the raspberry mixture until it comes to a boil, then reduce to a simmer for 7 minutes to allow the flavors to marry.
While the raspberry mixture is cooking, cut the skin and rind from the oranges, then cut the segments of flesh from between the membranes using a sharp knife.
Catch the segments in a bowl and set aside.
On a floured surface, roll out the puff pastry dough into a 12-inch x 14-inch rectangle. Gently transfer the dough to the prepared baking pan.
Using a small knife, score the crust 1 inch from the edge to create a margin. Poke the inside of the margin with a fork, sprinkle the edges with the remaining ¼ cup sugar, and place the crust in the freezer for 5 minutes to firm.
Bake the crust in the oven just until it becomes lightly browned, about 10 minutes.
Spread the raspberry mixture evenly inside the margin of the partially baked crust, then return to the oven and bake until the raspberry mixture bubbles and the crust becomes brown, about 10 minutes more.
Place 12 orange segments in 3 rows of 4 segments, each marking 1 serving of tart.