Preheat the oven to 350°. Heat the oil in a large skillet. Add the onion and cook over moderately high heat, stirring, until translucent, about 3 minutes.
Add the tomato, chiles, garlic and ginger to the skillet; cook for 3 minutes. Add the lamb and cook, stirring, for 6 minutes. Add the coriander, cumin and vinegar and cook over moderate heat for 10 minutes. Season with salt and pepper.
Brush the nan with olive oil and bake for 2 minutes. Spread the lamb on top and bake for 7 minutes. Sprinkle the cilantro over the pizzas and serve hot.