Fire roast or boil the Tomatoes (if boiling boil for 20 minutes after cutting the top portion and making 2-3 slits on the tomatoes so that it peels off easily and boil the whole dry Chillies too along with it. If roasting directly, roast in fire ( gas stove or charcoal fire), in this case soak the chilli for an hour in hot water, so that the dry chillies soften up and it's easy to grind ).
Whatever you do peel the tomatoes before grinding.