Loaded Cilantro Lime Cauliflower "Rice"

medium head cauliflower ((about 2 1/4 lbs))

olive oil

chopped green onions, (plus more for serving)

minced garlic ((2 cloves))

frozen corn, (thawed in a strainer under hot water and drained well on paper towels)

black beans, (drained and rinsed)

Salt

avocado ((fairly firm but ripe), diced)

large Roma tomato, seeded and diced

chopped fresh cilantro

fresh lime juice, plus 1 tsp lime zest