Using a meat mallet, bang chicken so it flattens to half its thickness. Season generously with salt.
Heat a frying pan with some oil and lay the chicken thighs skin side down. Cook on medium-high heat until the flesh starts becoming opaque from the bottom up. The skin needs to become nice and crispy so don't be tempted to flip the chicken over. When the flesh is cooked 3/4 of the way up, flip chicken thighs over and cook at the same temperature for a further minute. Remove from pan and let the chicken rest for 10 minutes. Keep chicken fat in the frying pan for when you are ready to fry the eggs.
Whilst the chicken is resting, cook ramen noodles according to packet instructions.
Combine all the gochujang sauce ingredients in a small saucepan and heat until bubbling. Add ramen noodles and coat well.
Using the chicken fat oil from the same frying pan, crack in eggs and fry over high heat until crispy around the edges. Season with salt.
Slice chicken thighs into strips.
Add noodles to a deep bowl, top with chicken slices, and fried eggs. Garnish with spring onions.