I actually eat small slices of raw onions (mostly red) because I love them so much. I also love pickled foods. I think it's not coincidence that pickled red onions are one of my favorite sandwich toppings.
Whenever I chop onions, I always pop in a few chopped pieces. Yes, I'm an ogre. Shrek: Ogres are like onions. Donkey: They stink? Shrek: Yes -- No! Donkey: Oh, they make you cry. Shrek: No. Donkey: Oh, you leave em out in the sun, they get all brown, start sproutin’ little white hairs. Shrek: No. Layers. Onions have layers. Ogres have layers. Onions have layers. You get it? We both have layers. Donkey: Oh, you both have layers. Oh. You know, not everybody like onions.
Um. They go really good with deli meats, especially bologna, ham, or turkey, and compliment mayo and lettuce really well. I'm not a fan of tomatoes, so I don't know how well the two go together. That said, they're absolute heaven with fish patty sandwiches, especially salmon or cod. Sadly, I've pretty much all but cut seafood out of my diet because I have a hard time reconciling eating food that comes from such an environmentally harmful industry. I haven't had a fish sandwich in over a year. Talking about it makes me want one. :( To give you some idea of what they taste like, my wife pickles red onions with red wine vinnegar, water, sugar, bay leaves, and regular pickling spices.
I've always wanted to get into pickeling, but I have an irrationally deep fear of botulism. I'll happily eat homemade pickles, but have a block about trying to do them myself. I miss out on so many good veggies from the farmer's market because I was too afraid to try and can them. Dented tin cans also sketch me out.