"Do you dry your Romas with skins on or off? And do you save seeds for two years or start over?"
I cut off the stem end and then peel a swath the entire length and back. If the tomato is large I'll peel another path from stem end to tip on opposite sides. But the slices always have some skin left intact. I've not read anything about dehydrating technique, just figure this, that the skins are tough and don't like that, but the skins are good for you so really shouldn't remove all. For our purposes, that method has worked to satisfaction.
I've never saved seeds from garden veggies, though do save some dill seeds and arugula seeds sometimes. I keep all of my garden seeds in the freezer except during planting time. Corn and sweet peas usually don't do well beyond the season, but then, tomatoes, cucumber, all greens, and most everything else seems to last for at least five or six years. Those seeds are saved until they get consumed. For some things I don't care about the variety, or just like random surprises. For those like cucumbers, squash, and salad blends, all seeds get dumped into one pack and luck of the draw determines which varieties actually get planted. For those mixed packs, when new seeds are purchased they get dumped in with the old. Always seems like the germination rate is pretty good.
I'm pretty sure that I've got some tomato seeds that are six to ten years old!