Cut out the core from each tomato and drop all the tomatoes into a large saucepan of boiling water. Let boil for about 15 seconds then drain. Peel the tomatoes, cut in half and squeeze out most of the seeds.
Preheat the grill. Line a baking tray with aluminium foil. Place the capsicums on the tray and grill, turning often, until the skins are slightly charred. Place them in a paper bag and seal it tightly (this will aid peeling).
Peel the capsicums and remove the cores. Dice the capsicums.
In a large, heavy frypan heat the olive oil then add the tomatoes, stirring. Cook over low heat, stirring occasionally until thickened, about 45 minutes. Add the capsicums, garlic, paprika, cayenne and salt.
Continue cooking, stirring and taking care it doesn't stick or burn, for about 15 minutes. Take off the heat and let cool. Chill until serving.