Combine all the Cabbage, Carrots, Onions, and Cucumbers in a large mixing bowl, set aside. In a non stick skillet, combine the Apple Cider Vinegar, Gochujang, Sugar and Salt. Bring to a simmer or until the sugar and salt are completely dissolved. Let the mixture cool slightly and pour it into the bowl with veggies and toss with tongs to combine. Set aside.