Since kale is very hearty and firm compared to romaine lettuce, spring mix or other common bases for salads, it is best to allow the kale to sit in the dressing for at least 30 minutes before eating. This will allow the kale to soften a little and make it much easier to chew and digest! If you don't have time to wait, try massaging the kale with some olive oil and lemon juice for a few minutes to soften it before you pour on the dressing and add in the toppings.