Cook broad beans in boiling water for 3 minutes. Drain and rinse with cold water. Peel off the skin.
Heat oil in a large, heavy-based saucepan over medium-high heat. Add cumin seeds and cook, stirring, until they sizzle, 10 to 20 seconds. Add onions, jalapeños, garlic and ginger. Cook, stirring often, until softened, 2 to 3 minutes. Add coriander, ground cumin and turmeric. Stir 10 to 20 seconds. Add water and cauliflower. Stir to coat well. Cover and cook until the cauliflower is almost tender, 15 to 20 minutes.
Stir in tomato and broad beans. Cover and cook until cauliflower is tender and beans are heated through, 2 to 3 minutes. Sprinkle with coriander and serve with lime wedges.
Jalapeño is a medium-hot chilli. Substitute 1–2 long red chillies if you are unable to find it.