Toast sesame seeds in a frying pan over medium heat, stirring often, until golden, 3 to 5 minutes. Scrape into a small bowl.
Whisk garlic, 2 tbsp. nutritional yeast, the soy sauce, sugar, vinegar, and sesame oil in a large bowl. Add kale and red onion and toss to coat. Sprinkle with sesame seeds, toss again, and serve. Add more yeast if you like.
*Find nutritional yeast at natural-foods and well-stocked grocery stores.