Rinse and cook the wild rice to your liking, either on the stove or in a rice cooker. This will take about 30 minutes.
Cover the walnuts with a cup of boiling hot water and let them sit to soften.
Thinly slice the leeks, discard the very top and the very bottom pieces. Thinly slice the garlic. Add the olive oil to a large pan and bring it to medium heat. Cook the leeks and garlic until they have softened, about 2-3 minutes. Then lower the heat and add the red pepper flakes. Season with salt and pepper to taste and continue to cook until they leek is very soft, about another 2-3 minutes. Set aside.
Using your preferred method, cook the sweet potato until fork tender.
In a small bowl, whisk together the soy sauce, hot sauce, red wine vinegar and cornstarch. Mix until slightly thickened and well combined.
Drain the walnuts and roughly chop them up.
In a large bowl, add the rice, walnuts, leeks and sweet potato. Drizzle in the soy sauce mixture. Use a clean hand to mix all the ingredients together.
Wet your hands to prevent sticking, and shape the mix into 8 equal-sized burgers. From here you can either freeze them and save them for later, or cook immediately.
If you are cooking immediately on the stovetop: Put a pan on medium heat and add a slash of oil. Pan fry the burgers for 2 minutes on each side or until they are dark and crispy.
If you are cooking immediately in the oven: Set the oven to broil on high and place a rack in the middle of the oven. Put the burgers on a baking sheet and spray the tops of the burgers with a cooking oil. Broil on high for 2 minutes, then flip and repeat on the other side.
Serve immediately on toasted potato buns with all your favorite burger toppings.