i'm not sure what you will consider processed as far as oils go...but something has to serve as a base to make any kind of seasoning "stick"...i use olive oil spray (it's like a cooking spray, but is just olive oil - in a can)...sounds gross, but you don't taste it once the potatoes are cooked. OR you can just use a scant amount of olive oil. Here's what i do:
Preheat oven to 425
I take 2 medium to large sized potatoes and cut them into wedges. Once they are all cut up, I put them into a gallon sized ziplock bag with like 1 tsp. of olive oil (or i spray them) and shake it until all the potatoes are covered. I then add black fresh ground pepper, oregano, basil and any other italian herbs (they do not have to be fresh, you can use the spice rack kind) and spices I have. I add minced garlic, too. I then shake up everything in the bag so that it's all evenly coated/ditributed. I then put them onto a cookie sheet and bake them until they look like they are getting a little brown and crisp...usually like 20 mins. after that, i put them onto a dish and sprinkle them with parmesan or romano cheese (like shaker pizza cheese), but you could omit that i suppose. They do taste really good though. Hope that helped.