Remove all of the green stems from the cauliflower and chop the head in half. Using a box grater (or a food processor), grate the whole head of cauliflower.

In a large skillet, heat the oil to medium-high and sauté the onion until fragrant and softened, about 5 minutes.

Add the jalapeño, and garlic and sauté another 2 to 3 minutes.

Add the grated cauliflower and cook, stirring frequently, until it begins to turn brown and cook down, about 5 to 8 minutes.

Add the diced tomatoes, salt, and chili powder and stir well to combine. Cook until much of the liquid is absorbed, about 5 minutes.

Add the chopped kale leaves and stir them into the mixture well. Cook until they have turned bright green and have wilted, about 3 minutes.

Serve cauliflower rice alongside your favorite entrée.