Preheat the oven to 220°C (425°F), Gas Mark 7. Mix the chickpeas in a bowl with 1 tablespoon oil, the cumin seeds and the paprika, and season with salt and pepper. Tip into a large nonstick roasting tin and roast in the preheated oven for 12–15 minutes, until nutty and golden.
Meanwhile, place the onion and tomatoes in a large bowl with the spinach leaves and toss gently to combine. Heap on to 4 serving plates.
Remove the chickpeas from the oven and scatter over the spinach salad. Crumble the feta over the top, if using, and drizzle each plate with the lemon juice and remaining olive oil. Garnish with lemon wedges and serve immediately.