Combine the ½ large head green cabbage, 3 medium carrots(shredded), ½ large white onion(thinly sliced), and 1 jalapeno (stem and seeds removed, sliced into thin strips) in a large bowl.
Combine the remaining ingredients in a separate bowl and whisk well to mix.
3 teaspoons kosher salt, 2 teaspoons dried oregano, 1/2 cup apple cider vinegar, 1/4 cup water
Pour the dressing over the cabbage mixture and stir. Taste and add additional salt, if needed. Cover and refrigerate for at least 2 hours or overnight (preferred) before serving.