I don't have anything particularly original or insightful to say about ceviche, but I've been making it a lot what with the heat recently and the last batch I made turned out so prettily I needed an excuse to post it.
I've done research on the regional variations on ceviche all around Latin America and I just ended up confused. I can't figure out what sort comes from where or why different ingredients show up in different places. I've taken to just throwing together what I've got handy in various combinations and hoping for the best. Usually it works out fine. I use a one from column A, one from column B procedure to guide me to make sure I build up enough different flavors to make something interesting and to build up enough stuff in the bowl so I get a full dinner out of it.
Nearly any sort really, in chunks, slices, chopped or even ground. There are a few guidelines, though. The lower quality the fish I'm using, the smaller I cut it and the longer I marinate it. Raw shrimp is not only unsafe, but it has an unpleasant texture so it's best to cook it a little first. The same goes for sea scallops, but bay scallops are quite nice raw. You can see both of those in the picture. Those are tiny coldwater shrimp from Canada and tiny scallops from Argentina.
White, red or green. I like white or red onion chopped fairly fine, but I prefer scallions in larger pieces.
Sweet or hot, sliced thin. Red is nice for the color.
Cilantro is used some places, parsley in others. Some use neither. I prefer cilantro usually. I think I actually used culantro the day of this particular batch.
Hominy and/or corn nuts are traditional, but I never have them around so I just use plain old corn kernels and I like it fine. I think a chunk of corn on the cob might be traditional in Peru.
Other possible additions:
Tomatoes-I like fresh, seeded and cut in fairly large pieces. Some use tomato juice as part of the marinade, but I never have that around.
Avocado-I always put it in when I've got it, it adds a nice textural contrast, but not too much to the flavor.
Cucumber-not at all traditional, but it works in a tartar and it works here too. Seeded and finely diced.
Celery-I understand some people add this. I can't see why.
I use lime juice usually, sometimes mixed with lemon. Bitter orange juice is fairly common, but I don't care much for it myself. Grapefruit doesn't work at all. I usually don't marinate very long at all (as is the modern style), particularly if I'm using something that doesn't need the chemical cooking. Longer marinations are useful mainly just for white fish or lower quality tuna.
Crackers, corn chips, sliced sweet or white potato, plantains or popcorn. I find popcorn gets mushy quickly if you try to add it to the mix, so that's best served on the side. Homemade corn chips are my favorite.
Vinegar based is best. Tabasco is fine, but I like a Peruvian-style hot sauce with a more rounded flavor that I picked up down at one Fairchild festival or another. Check my archives; there's probably a picture of the bottle. Don't use too much, particularly if there are hot peppers in the mix. Ceviche should be seriously sour and hot, but you need to be able to taste everything else too. I've had a white sauce with Peruvian ceviche that would make a nice alternative but I don't know what's in it and I can't find a recipe. Anyone know?
I find ceviche is a really good choice for a weekday dinner when I don't want to stay in a hot kitchen too long. I know my version is a bastardization of a whole host of cuisines, but if I'm too hot and tired to properly cook, I'm too hot and tired to care much about that sort of thing either.