Position rack to middle of the oven and heat to 325.
Oil sides and bottom of 9 1/2" fluted tart pan with removeable bottom with vegetable oil.
In food processor, grind gingersnaps until they are the texture of sand. Transfer to a bowl, add melted butter, working it in by squishing with the hands. Press into sides and bottom of pan. Set in refrigerator for 20 minutes until firm.
Bake crust on baking sheet for 15 minutes until fragrant--don't let it get too dark. Cool on rack.
Meanwhile, pass 1 cup berries through food mill with fine disk or force threough fine sieve with wooden spoon into medium bowl, about 1/2 cup puree. Discard contents in strainer.
Put chocolate in medium bowl. Heat cream until just boiling. Pour hot cream over chocolate, whisk to blend. Stir in raspberry puree and salt. Pour ganache into cooked tart shell.
Refrigerate ganache until fairly firm, about 1 hour.
Arrange remaining berries on top of ganache, covering whole surface.