Well - you'll pleased to know that you’re already off to a good start - as Roma tomatoes are absolutely ideal - so much so - that they are generally the first choice when its comes to drying - as not only do they usually have very few seeds - but as they have a much lower water content than other varieties - they dry much better and are way tastier too As to salting - although its not necessary to salt tomatoes prior to or during the drying process and it is therefore more a matter of choice rather than being a necessity - it won't affect the drying process if want a slightly salty end result - to give them a light sprinkling of salt prior to putting in them oven or even a light dusting of herbs or spices - depending on the flavor you are after. Either way looking forward to hearing how you get on.