Heat olive oil in a large pot with lid over medium heat.
Add onion and cook 5 to 7 minutes, stirring occasionally until just beginning to brown.
Add garlic and 1.5 tsp of salt. Cook for 3 to 4 more minutes until fragrant and golden.
Add cauliflower and water, pushing cauliflower down to submerge as much as possible. It's okay if it's not all submerged. Bring to a boil, cover pot, and reduce heat to low. Simmer 12-14 minutes. Cauliflower is done when it is tender enough that a knife easily slides into it.
When cauliflower is done, add kale. Return to a boil, cover and simmer for 2-3 minutes until kale is bright green and tender.
Working in batches, scoop contents into a blender. Make sure you get both liquid and solids. Puree until smooth and add to a large bowl. Repeat for the rest of the soup. It should take 2-3 batches depending on the size of your blender.
To serve, top each bowl of soup with a few splashes of tamari, soy sauce, or a pinch of salt.