Thin slice chicken breasts to about ¼ to ⅛ inch thin. Season them with ingredients from coconut aminos to olive oil. Mix well and set aside in the fridge while preparing others.
Press the kimchi, with a little pressure and using the back of a spoon, to drain through a sieve with a bowl under to catch the kimchi juice.
Prepare the zucchini noodles, if using. Chop the garlic and scallions.
In a well-heated large stainless steel skillet or cast iron or wok, add 1.5 tbsp cooking fat. Sear the chicken breasts in one even layer over medium-high heat without disturbing until they are in golden brown color, about 2 minutes, then use a spatula with a firm tip to flip. Cook the flip side about 1 minute. The chicken should be almost cooked through before setting them aside along with the pan juice and oil in the skillet.
Use the same skillet and add 1.5 tbsp cooking fat, saute garlic and white scallion parts over medium heat until fragrant. Season with a pinch of salt and stir fry frequently to prevent them from burning ,about 8-10 seconds.
Turn the heat up to medium-high. Add the drained kimchi, saute for 1 minute. Add zoodles, if using, and toss for 30 seconds.
Return chicken to the skillet and add 4-5 tbsp kimchi juice. Toss for 30 second. Taste test and see if you want to add the coconut aminos.
Off heat. Garnish with green scallion parts and sesame seeds, if using. Drizzle with sesame oil. Serve warm.
If desired to make a thicker sauce, after all the ingredients are cooked, scope out the kimchi, chicken, and zoodles and reduce the sauce to make it thicker by turning up the heat for a few minutes then pour it over the dish.
My homemade Paleo/Whole30/Keto Kimchi is also great, too! If you are doing Whole30, use my homemade version. Most store-bought version that tastes authentic usually contains some small amount of sugar.