This is very similar to one of my favorite winters salads I've been making for years. I found the recipe originally on a package of Earthbound Organics baby spinach in the late 90s. The only difference is I use baby spinach and an orange vinaigrette I make with orange juice in it. I would NOT recommend subbing canned oranges for this. The fresh oranges are key here and the red onion & feta compliment them so well. I sliced mine in rounds and then remove the peel. Would probably taste great using grapefruit or tangerine too but I like the orange, especially when they're in season. Good for a dinner party to impress guests but also simple & easy to assemble. Sometimes I add spiced walnuts or pecans if I have them around which are delicious with this but I usually stick w/ the basic recipe.