thanks for the recipe philso, please allow me to make a couple of observations:
- the addition of tomatoes in ceviche is exclusive to Mexico and is rarely used anywhere else
- the fish in ceviche is typically diced into little cubes, but i have also seen it in fine slices like you mention - peruvians have a term for this type of presentation in slices calling it "tiradito" in which they also omit the onions
- throughout most of latin america, ceviche almost always has some tyoe of chili or heat in the form of hot sauce in it, doesn't have to be too spicy
- and lastly, traditionally the preparation is always done with lime juice - in particular, "limon criollo" which is a lime that is smaller than the "persian limes" common in the u.s., these limes are similar lookking to florida's key limes in that they are perfectly round, golf ball size, have a lot of juice for their size, and have a very thin skin and rind - in latin america, the yellow "lemons" are seldomly used in any kind of preparation as the taste is very different
(on this note, cliveb and i touched on this here -
http://www.discusscooking.com/forums/f76/chimichurri-sauce-tnt-7559-2.html)
every country has its own preparation and i like your recipe in that it only allows for the fish to be marinated in the citrus for an hour before serving, i have served it even with as little as 10 minutes marination - most countries call for marinating for several hours, even days which imho the lime totally overpowers the delicate fish flavor... also, always use the freshest fish possible since no heat will be applied in serving it and the taste of not-so-fresh fish is very noticeable.... another suggestion is to stick to fish with white-flesh such as sea bass and grouper