Place peanuts in the bowl of a food processor. Turn the food processor on and let it run until the peanuts are finely chopped to the point of crumbs.
Transfer the chopped peanuts to a shallow bowl. Add the breadcrumbs, garlic powder, and salt. Stir together with a spoon or just mix it up with your fingers.
Place the flour in a separate shallow bowl.
In a third shallow bowl, whisk together the egg and water.
With one hand, coat one piece of tofu with flour, shaking off any excess. Using your other hand, dip it into the egg mixture, allowing any extra to drip off. Using your first hand again, flip the tofu around in the breadcrumb mixture, pressing gently to adhere to all sides.
In a large cast iron skillet, heat coconut oil over medium heat. Add the tofu, working in batches if necessary so as not to crowd the pan. Allow to cook for 2 minutes, then flip and cook 2 minutes more or until the coating is golden brown. Repeat with any remaining tofu, adding more coconut oil to the pan if necessary.
Serve the tofu sprinkled with toasted sesame seeds if desired.