Massage the kale to soften it and reduce bitterness. Use fresh lemon juice for best flavor and toast sunflower seeds to enhance their nutty taste. Adjust sweetness of the dressing to your preference. This salad can be made ahead and stores well for up to 2 days in the fridge, preferably with dressing stored separately to keep kale crisp. Customize by adding proteins, different nuts or seeds, cheese, or dried fruits.