Personally I would not use the peel if they are not organic, but you may feel differently. At the very least scrub them well if you plan to use the peel. And then you could make marmalade. Or you could juice the oranges, freezing the extra. You could grate the zest, and either dry it or put it (in recipe sized amounts) in ice cube trays, cover with some of the juice, and freeze, and then you'll have "fresh" zest for recipes in the future. You could use a vegetable peeler to get bigger, slightly thicker peelings, and candy them - if done with care they make attractive little nibbles alongside after dinner coffee; if done a little more haphazardly (like I do them) they are nice chopped up in holiday breads and cookies.
All of these suggestions work equally well for lemons, or grapefruit.
We candy the peel. Cut it in strips, remove the pith, boil three times for maybe 20 minutes each time, the last time in syrup. Remove and roll in granulated sugar and then allow to dry. The next day, dip them in melted chocolate.
Then you can squeeze the flesh for juice or cut it in circles for salads or maybe even dehydrate it.
I also have dehydrated the zest and then run it through a spice grider/coffee bean grinder, to make citrus powder, which I then added to recipes as a flavor enhancer. Did the same with lemon and lime, and dusted them on shrimp or poultry.
