Before starting to prep the tofu steaks, wash hands with soap and water for 20 seconds.
Press tofu using a tofu press or place it between two plates. Put a heavy book or object on the top plate to add weight. Press water out of the tofu brick for at least 30 minutes. If possible, press it for an hour.
While tofu is pressing, make the marinade. Whisk together soy sauce, rice vinegar, water, toasted sesame oil, garlic, brown sugar, liquid smoke, and red pepper flakes.*Can be made up to 48 hours in advance.
Remove the tofu from the press or the plates when enough water has seeped out. Cut it in half horizontally and then lengthwise so that you have 4 slabs, each about an inch thick.
Place the tofu slabs in a square glass baking dish, and pour the marinade over the slabs. turn the slabs to coat all sides in the marinade. Marinate for at least 20 minutes or overnight, occasionally turning so that each side is evenly flavored.
When you are ready to cook the tofu, remove it from the marinade. Place the marinade in a small pan and set it aside.Coat each tofu slab on both sides with steak seasoning. Heat up a grill pan so it is very hot, and brush it with sesame oil. (Or, use another oil with a high smoke point like grapeseed or avocado. You can use one of these oils in spray form if you can find it.)
Place tofu slabs on the grill pan and cook for 3 to 4 minutes per side.
While tofu is grilling, place the pan with marinade on a burner on medium-low heat. Add cornstarch and bring to a boil to thicken slightly. You may need to add a couple of Tablespoons of warm water to thin it slightly.
Serve tofu slabs hot with a dollop of sauce over the top or on the side.
Notes
Mix the steak seasoning with a teaspoon of cornstarch when baking the steaks instead of grilling. The cornstarch makes the exterior a little crispier!