Heat a large skillet over medium heat. Once the pan is hot, add the riced cauliflower, crushed tomatoes, roasted red peppers, giardiniera, balsamic vinegar, capers, garlic, dried basil, oregano, and red pepper flakes. Cook for 15 minutes or until the cauliflower is tender, stirring occasionally. Then, add in the baby spinach and cook another 8 to 10 minutes or until most of the liquid has cooked off, stirring frequently. Add the sea salt and adjust seasoning according to taste preferences. If you added the giardiniera and capers, 1/4 teaspoon of salt will likely be plenty; however, if you skipped on one or both, I suggest adding more to season it properly.