Preheat oven to 350 degrees. In the bowl of a food processor, blend flour, salt and sugar. Add butter and process until mixture resembles small peas. With the motor running, slowly add the ice water until the mixture comes together and forms a ball. Do not process for more than 30 seconds and do not allow the mixture to get wet and sticky. Turn out on seran wrap, shape into a disc and refrigerate for for at least one hour. After the dough has chilled, roll out between sheets of parchment paper into a 12 inch round. Using your rolling pin, lift the tart dough onto it and carefully place into a 9 or 10-inch false bottom tart pan. Carefully arrange the dough without stretching to fit the pan. Roll your pin across the top of the tart shell to trim the pastry. Return to refrigerator.
Take whole head of garlic and place on a sheet of foil. Drizzle with olive oil and fold foil around head of garlic. Bake for 1 hour. Remove from oven and cool. Raise oven temperature to 450 degrees.
Slice tomatoes into 1/4 inch slices. Slice top off head of garlic. Remove tart shell from refrigerator and squeeze the head of garlic into the bottom of it. Spread the garlic paste over the entire bottom of the shell. Sprinkle half of grated Fontina on top of the garlic paste. Decoratively arrange sliced tomatoes on top of cheese. Sprinkle tomatoes with kosher salt and freshly cracked pepper to taste. Top with remaining grated Fontina and lightly drizzle with olive oil.
Put tart pan on a cookie sheet and place in oven. Reduce temperature to 400 degrees and bake for 45 to 55 minutes until tart shell is nicely browned. Cool for 30 minutes. Serve warm with a bibb lettuce salad and a chilled Sauvignon Blanc.