Very finely shred the green cabbage using a mandolin, vegetable peeler, or a sharp knife. Place it in a large bowl.
Add the white vinegar, oil, sugar, toasted sesame seeds, sesame oil and celery salt to a screw-top jar. Shake until well combined and the sugar has dissolved. You can also whisk the dressing in a bowl if preferred.
Pour the dressing over the cabbage and add sliced spring green onions if using. Toss until evenly coated.
Garnish with extra toasted sesame seeds and serve immediately.