Heat 1 tablespoon oil in a large skillet over medium-high heat. Cook the onion with the cut side down about 5 minutes, until it has browned around the edges. Transfer to a large saucepan.
Add the garlic, cinnamon, anise, coriander, and red pepper flakes to the skillet and stir until fragrant, about 1 minute, then add to the saucepan with the ginger and broth. Bring to a boil, then reduce the heat to a simmer.
Heat the remaining oil in the skillet. Season the pork steaks with salt and pepper to taste and cook through, 4-8 minutes per side depending on how thick the cuts are. Transfer to a cutting board and let rest 5 minutes before slicing thinly and dividing equally between 4 serving bowls along with the spiralized zucchini.
Strain the broth and ladle equal parts into each of the bowls. Garnish with green onion, cilantro, and lime wedges before serving.