Cook the pasta according to the package directions. If you are using dried pasta (like pictured), it will likely take around 12-15 minutes. Before draining, reserve some of the pasta water.
While the pasta is cooking, prepare the soup. In a large pot, heat the olive oil over medium heat and sauté the chopped onion for 2-3 minutes until softened. Add the garlic and cook another minute or two. Season with red pepper flakes and a generous sprinkle of salt and pepper.
Add the tomatoes with their juices, as well as the fresh orange juice. Cook another couple of minutes and then puree. You can do this with an immersion blender or in a blender.
Add the cooked pasta and a 1/4 cup of pasta water to slightly thin the soup. If needed, you can add a little more pasta water. Taste and season with more salt and pepper if needed. Serve with Parmesan and chopped fresh herbs (parsley, basil, or cilantro).