Finely dice cucumber, tomato and spring onion, drizzle with a little oil and vinegar, leave to marinade. Drain chickpeas and coat with sumac then roast in oven until slightly golden. Slice aubergine, place on a wire rack, sprinkle with salt and leave to remove excess moisture. Heat a little oil in a frying pan and cook aubergine until soft and nearly mushy, remove to a plate and keep warm. Warm flatbread then spread with a layer of houmous, add aubergine, tomato salad and spiced chickpeas. Drizzle with yoghurt and chimichurri, finish with mango, chopped parsley and a dusting of sumac