Remove the core and let the cauliflower dry completely. Coarsely chop into florets, then place half of the cauliflower in a food processor and pulse until the cauliflower is small and has the texture of rice or couscous – don't over process or it will get mushy. Set aside and repeat with the remaining cauliflower.
Heat a large saute pan over medium heat, add olive oil, scallions and garlic and sauté about 3 to 4 minutes, or until soft.
Raise the heat to medium-high. Add the cauliflower "rice" to the saute pan. Cover and cook approximately 5 to 6 minutes, stirring frequently, until the cauliflower is slightly crispy on the outside but tender on the inside. Season with salt and pepper to taste.
Remove from heat and place in a medium bowl; toss with fresh cilantro and lime juice to taste.