Rinse the kale leaves, cauliflower, cherry tomatoes, green onion, and parsley under cold water; shake off excess water and pat dry with paper towels or a clean kitchen towel.
Remove the tough center stalk from each kale leaf: hold a leaf by the stem and strip or cut the leafy part away from the thick midrib. Discard the stalks.
Stack the kale leaves, roll them into a loose cylinder, and finely chop (mince) the leaves with a chef’s knife. Transfer the chopped kale to a large bowl.
Halve the cherry tomatoes and add them to the bowl with the chopped kale.
Trim the root end of the green onion, then finely chop the white and green parts; add the chopped green onion to the bowl.
Remove the parsley leaves from the sprig, finely mince the leaves, and add the minced parsley to the bowl.
Remove the core from the 1/2 head cauliflower and cut into pieces that will fit your box grater. Using the large holes of a box grater, grate the cauliflower and add the grated cauliflower to the bowl with the other ingredients; toss to combine.
In a small bowl, whisk together 2 tablespoons freshly squeezed lemon juice, 1 clove garlic (finely minced), 1/2 teaspoon kosher or sea salt (or 1/4 teaspoon table salt), freshly ground black pepper to taste, and 2 tablespoons extra virgin olive oil until combined.
Pour the dressing over the salad and toss gently until evenly coated. Taste and adjust seasoning with additional salt or pepper if desired. Serve.