To make the sauce, pulse tomatoes with their juice in a food processor until finely chopped. Heat 2 tablespoons olive oil in a large straight-sided skillet over medium. Cook onion and red pepper flakes, stirring occasionally, until onion is softened, about 8 minutes. Add minced garlic and tomatoes; bring to a boil. Reduce heat and simmer until thickened, about 20 minutes. Coarsely crumble tofu and stir into sauce with chopped oregano and basil; season with salt. Let cool.
To make the lasagna: Preheat oven to 375°F. Slice zucchini lengthwise into thin strips using vegetable peeler. Place 5 or 6 zucchini slices, overlapping slightly, in the bottom of an 8-inch square baking dish. Top with 1 cup sauce. Dot evenly with 1/4 cup ricotta and sprinkle with mozzarella. Repeat twice with zucchini, remaining sauce, and 1/2 cup cheese. Top with remaining zucchini; brush with 1/4 teaspoon olive oil. Dot with remaining ricotta and evenly sprinkle with the rest of the mozzarella and season with pepper. Bake, uncovered, until lasagna bubbles and top browns, 50 to 60 minutes. Let stand 10 minutes before serving.