Wash and dry 1 bunch kale, then pat leaves dry with a clean towel. Strip leaves from thick stems, discarding stems, then thinly slice leaves. Transfer to a large bowl.

Trim knobby end of 6 oz. brussels sprouts and pull off any dried or gnarly outer leaves. Cut all brussels in half lengthwise, then arrange halves cut side down on board and very thinly slice. Add to bowl with kale.

Drizzle dressing over kale mixture; season with salt and pepper. Toss with your hands to coat.

Add cheese and sunflower seeds and toss lightly to incorporate.

Do Ahead: Dressing, kale mixture, and toasted sunflower seeds can be prepared 8 hours ahead. Cover dressing and kale mixture separately and chill. Cover sunflower seeds and store at room temperature.