Heat the olive oil in a large skillet over medium heat. Add the onion and cook for 4 minutes until softened.
Stir in the garlic and ginger and cook for 1 minute until fragrant.
Add the cumin, turmeric, garam masala, and chili powder. Cook for 30 seconds to toast the spices.
Pour in the chickpeas, diced tomatoes, and vegetable broth. Season with salt and pepper. Simmer for 12 minutes, stirring occasionally, until the sauce thickens slightly.
While the curry simmers, pulse the cauliflower florets in a food processor until they resemble rice. Place in a microwave-safe bowl, cover, and microwave for 4 minutes.
Steam the spinach in a separate pot or steamer basket for 3 minutes until just wilted. Drain any excess water.
Divide the cauliflower rice among four bowls. Spoon the chickpea curry over the rice and add the steamed spinach on the side. Top with chopped cilantro if using.