Heat the olive oil in a 3-quart saucepan over medium heat. Add the garlic and cook for about 30 seconds, stirring, until fragrant.

Stir in the crushed tomatoes, oregano, 1 teaspoon of the kosher salt, and the black pepper. Bring to a simmer, reduce the heat to low, and cook uncovered for 20 to 25 minutes, stirring occasionally.

While the sauce simmers, trim the eggplants and cut them crosswise into 1/2-inch slices. Arrange in a single layer, sprinkle both sides with the remaining 2 teaspoons kosher salt, and let stand for 30 minutes.

Rinse the eggplant slices under cold water and pat them very dry with paper towels.

Heat the oven to 375°F.

Put the flour in one shallow bowl, beat the eggs with the water in a second bowl, and put the breadcrumbs in a third bowl.

Coat each eggplant slice in flour, shaking off the excess, then dip it in egg and coat it in breadcrumbs.

Heat the canola oil in a 12-inch skillet over medium heat to 350°F. Fry the slices in batches for 2 to 3 minutes per side, until golden brown and tender, then drain on paper towels.

Spread about 1 cup of sauce in the bottom of a 9x13-inch baking dish. Arrange half the eggplant in the dish, spoon over half of the remaining sauce, and sprinkle with half of the mozzarella and Parmesan; repeat with the remaining eggplant, sauce, and cheeses.

Bake uncovered for 25 to 30 minutes, until the sauce is bubbling and the cheese is browned in spots.

Let rest for 15 minutes before serving.