In a large mixing bowl, combine light oil, sesame oil, gochujang, gochugaru, soy sauce, light brown sugar, minced ginger, minced garlic, white pepper, and 1 tsp salt. Stir completely until a paste has formed and set aside.
On a large cutting board, lay out your chicken breasts. Spread a piece of plastic wrap over each.*
Using a meat tenderizing mallet**, pound the chicken breasts flat so that you have a larger, thinner piece of meat to work with.
Put your flattened chicken breasts in the bowl of marinade and flip several times until both are completely coated with the sauce. Cover and store in the fridge for 1 hour to overnight.
When you’re ready to cook or while your chicken is marinating, run the uncooked rice under cold water until the water runs clear.***
In a small pot, add uncooked rice, water, lime zest, lime juice, and remaining 1 tsp salt. Cover and cook on low heat for 20-25 minutes. When finished, remove from heat and set aside without removing the lid.
Heat grill, grill pan, or skillet on medium-high. Lay marinated chicken breasts flat and cook for 20-25 minutes, flipping in increments of 5 minutes. If desired, baste with the remaining marinade on the first two flips.
When completely cooked through, remove chicken and set aside. Cover and let rest for 10 minutes. Slice into strips and serve with lime rice. Garnish with sesame seeds, soy sauce, and/or additional lime juice. Enjoy!