Prep the sauce. Whisk together the brown sugar, soy sauce, sesame oil, garlic, ginger, and a few pinches of crushed red pepper flake. Set aside until ready to use.
Heat a large skillet over medium heat with enough olive oil to coat the bottom of the pan. Very thinly slice the chicken against the grain and toss in a bowl with the flour. The chicken may stick together a bit - that's ok!
When the oil is hot, fry the chicken in one layer (I do this in two or three batches) for about three minutes on each side until just barely golden. Remove the chicken to a plate and turn the heat OFF.
To the hot skillet, add the Korean sauce and stir to deglaze the pan. Add the chicken to the sauce and stir to coat and warm through.
Serve the chicken over rice with zoodles and any Asian pickles, if you'd like. Enjoy!