Drizzle the sweet potato and white potato wedges with 3 tablespoons of the olive oil in a large roasting tin and toss well, then scatter over the poppy and sesame seeds and chilli flakes and toss again. Season generously with salt and pepper and roast in the top of a preheated oven, 200°C (400°F), Gas Mark 6, for 35 minutes until golden.
Meanwhile, put the pepper wedges and tomatoes in a smaller roasting tin, then drizzle with the remaining olive oil and toss well. Roast on a lower shelf in the oven for 25 minutes until softened and lightly charred in places.
Transfer the roasted pepper and tomatoes to a food processor, season generously with salt and pepper and add the smoked paprika. Process until almost smooth but with a little texture still remaining. Spoon into a small serving bowl and place in the centre of a serving platter.
Arrange the roasted potato wedges on the platter, scatter with the chopped coriander and serve.