Heat oil in a dutch oven over medium high heat. Add onion to pan and sauté until softened, stirring frequently. Add oregano, garlic, sea salt, and pepper and heat through. Stir in squash, zucchini, and carrot sauté about 5 more minutes or until vegetables are tender. While the vegetables are cooking, place all but one cup of the chopped Roma tomatoes and a small amount of the broth in a blender and blend to a smooth consistency. Add the tomato mixture along with the remaining chopped tomatoes, beans, and the remaining broth. If using kale, add it here. Bring to a boil. reduce heat; simmer about 20 minutes.
Remove from heat. If using spinach, stir it in here along with additional sea salt and pepper if desired. Top with grated cheese.