To make the tarts, preheat the oven to 200 celsius (390 Fahrenheit). Place the pumpkin slices in a bowl and add the olive oil and season with salt and pepper. Toss to combine and then place in a single layer on a baking tray lined with non stick paper. Bake for 20 to 25 minutes or until tender.
Toast the cumin and coriander seeds in a frying pan over a medium heat until fragrant. Set aside to cool. Once cooled add to a food processor fitted with a steel blade and process until a powder forms. Add the remaining ingredients and process until you have a smooth paste. Set aside while you make the tarts.
To make the Harissa, preheat the oven to 200 degrees Celsius (390 Fahrenheit) and place the capsicum on a tray lined with baking paper and roast until the skin is black, about 20 to 25 minutes. Remove from the oven and place in a plastic bag, seal and allow to cool. Once cooled you should be able to easily remove the skin. Discard the stalk and seeds.