Step 1

Combine red onion and vinegar in a small bowl; add ½–1 chile, depending on the heat of your chile and your preference; season with salt and pepper. Let sit 10 minutes. Whisk in garlic, yogurt, oil, and lemon zest and juice; set dressing aside.

Step 2

Cut cabbage in half through core. Remove core; discard. Tear leaves into 2" irregular pieces and place in a large bowl. Season with salt and massage and scrunch firmly with your hands for a minute or so to soften. Pour reserved dressing over cabbage and toss with your hands to coat. Season with more salt if needed (cabbage can take a good amount of salt).

Step 3

Toss in dill just before serving.

Step 4

Do Ahead: Dressing can be made 12 hours ahead; cover and chill. Slaw (without dill) can be made 1 day ahead; cover and chill.