Cut the cauliflower into large chunks. Pulse a few times in the food processor until the cauliflower is chopped to the size of rice. You may need to do this in batches. Make sure to include the stems and florets.
Heat the olive oil in a large skillet over medium high heat. Add the garlic, cooking until fragrant, about 30 seconds. Stir in the cauliflower rice, red pepper flakes, salt and pepper and sauté for 3 minutes. Fold in the tomatoes, olives, artichokes, spinach and parsley. Cook for 2-3 minutes until the rice is heated through and the spinach has wilted.
If you don’t have a food processor, you can also use the large holes of a box grater. Or, it is fine to just buy riced cauliflower.