Remove the core and let the cauliflower dry completely.
Roughly chop the cauliflower into florets, and place half the cauliflower in a food processor. Pulse until the cauliflower is small and resembles couscous. Set aside and store the other half of cauliflower for a later time.
In a large skillet over medium heat, heat the olive oil, then add the onions and garlic and cook until soft and translucent, about 5-7 minutes.
Add the cauliflower rice and stir to combine. Season with salt and pepper and continue to cook, stirring frequently until the cauliflower softens, about 3-5 minutes.
Remove from heat and transfer to a large serving bowl. Add lime juice and fresh cilantro and toss gently to combine. Serve warm
Storage: Store any leftovers in an airtight container. They will last about 4-5 days in the fridge or up to 3 months in the freezer.