Add about 4 cups of water to a saucepan and bring to a steady low boil. Alternatively, you can set up a steamer to steam the kale.
Turn the heat off of the water and add the kale to the boiling water for just a minute or two, and then remove them using a slotted spoon or tongs.
Add the kale, onions, avocado, garlic and lemon juice to a food processor and pulse until mostly chopped and somewhat creamy in texture. Add more lemon juice or some water if it's too thick.