Place the white onions and garlic in a food processor and pulse until the onions are finely diced.
Heat the coconut oil in a large skillet on medium high heat and add in the diced garlic and onions.
Cook the onions for 3 to 4 minutes until they begin to soften.
While the onions are cooking cut the head of cauliflower into florets and place in the food processor. Pulse until they are broken down into small rice sized pieces.
Add the cauliflower rice to the skillet, sprinkle with salt and cook for 2 minutes before adding in the coconut milk and lime juice. Cook the rice for 8 minutes stirring frequently until the rice has completely softened and the liquid has evaporated.
Sprinkle the rice with lime zest and chopped cilantro before serving.