Core and somehow turn the cabbage into very thin shreds, ribbons, slices, etc. Peel and shred carrot. Stem, deseed, and mince jalapeño. Grate the shallots.
Whisk vinegar, water, sugar, and salt in large bowl until sugar is dissolved.
Rub the dried oregano between your palms to release its oils, then add it with the cabbage, grated shallots, carrot, and jalapeño and toss to combine. If needed, set a plate or small bowl on top to keep everything submerged. Cover and refrigerate for at least 1 hour, preferably at least 6.
Serving
Toss the slaw, then chop the cilantro and stir it in. Serve using a slotted spoon or tongs so the curtido comes out a bit juicy rather than drained.
