Combine Chicken marinade ingredients in large bowl. Mix with spoon. Add chicken. Mix until well combined. Cover and place in fridge. (Marinate at least 1 hour, but preferably overnight.) If your rice cakes are frozen, add to a small bowl and cover with cold water. Set aside. (Rice cakes can keep this way, tightly sealed, in the fridge for 2-3 days).
Place Fire Sauce ingredients in food processor. Puree until no large chunks remain. Set aside.
Preheat oven to 350F/176C.
Heat cast iron skillet over medium-high heat. Add about 1 Tbsp of oil to coat the bottom of the pan. When the oil shimmers, add the chicken. Brown the chicken in batches, one layer at a time, making sure not to crowd the pan. It's ok if the chicken is not fully cooked.Transfer to a clean plate. Repeat process until all the chicken is cooked. Place all the browned chicken back into the skillet. Pour the Fire Sauce on top, making sure to scrape every last bit with a spatula. Mix around with a spatula until chicken is completely coated in sauce.
Reduce heat to medium and simmer until the sauce becomes dark red, thick, and reduced, about 12-15 minutes. The chicken and sauce should bubble somewhat vigorously. Lower heat, if needed. Feel free to add water if the sauce looks too dry (about 1 Tbsp at a time). Keep an eye on the sauce, mixing it from time to time.
Remove skillet from heat. Drain rice cakes and scatter over the chicken and fire sauce mixture.
Sprinkle the cheese on top of the rice cakes and chicken, making sure to coat evenly.
Place skillet in oven until cheese melts, about 5-10 minutes. It should be a gentle melting of cheese. Watch carefully and make sure it doesn't overcook!
Remove from oven. Garnish with sliced green onion and sprinkle of sesame seeds, if desired. Serve immediately with rice and enjoy!