Preheat the oven to 400°F and line a baking sheet with parchment paper.
Begin preparing the congee while the oven heats up. Place 8 cups of water into a large pot and place it over high heat. Rinse the rice under cold water, then add it to the pot, along with the ginger slices, and garlic slices. Bring the liquid to a boil, stirring occasionally. Once the water boils, reduce the heat and let the rice cook at a low simmer for 30 to 40 minutes, stirring occasionally and making sure to scrape any rice from the bottom of the pot with your spoon.
To make the baked tofu, stir the soy sauce, cornstarch, vegetable oil, and sesame oil together in a medium bowl. Cut the tofu into 8 slabs, then add them to the bowl. Gently rub the seasonings into the tofu with your hands, getting the slabs well coated. You can do them individually or all at once — whichever is easier for you.
Arrange the tofu slabs on the baking sheet. Don't worry if some liquid remains in the bowl. Bake the tofu slabs for about 40 minutes, turning halfway through, until they're browned and crispy.
Make the quick-pickled veggies while the congee simmers and the tofu bakes. Place the rice vinegar, sugar, sesame oil, and salt into a small bowl. Stir to dissolve the sugar and salt, then add the sliced cucumber and carrots. Stir to coat the veggies in the pickling mixture, then let them soak until the congee and tofu are ready, at least 15 minutes.
Once the congee has simmered for 30 to 40 minutes, it should have reached a thick, porridge consistency. Take the pot off of heat. Stir the hot water and miso paste together, then stir it into the congee (Note 1). Season the congee with salt to taste.
To serve, ladle the congee into bowls. Arrange pickled veggies on top, draining them well as you remove them from the pickling liquid. Cut the tofu slabs into strips, then arrange the strips over the veggies. Optionally, drizzle with toasted sesame oil and/or chili oil. Sprinkle with cilantro, scallions, and/or sesame seeds. Enjoy!