Red-Snapper Ceviche

2 pounds fresh, deboned red snapper (or other firm-fleshed fish) fillets, cut into 1/2-inch pieces
1/2 cup freshly squeezed lime juice
1/2 cup freshly squeezed lemon juice
1/2 red onion, finely diced
1 cup chopped seeded fresh tomatoes
1 serrano chili, seeded and finely diced
2 teaspoons kosher salt
Pinch ground oregano
Dash Tabasco or a light pinch of cayenne pepper
To serve:

Cilantro
Avocado
Tortillas or tortilla chips

Method
Assemble the ceviche:
In a non-reactive casserole dish, either Pyrex or ceramic, place the fish, onion, tomatoes, chili, salt, Tabasco, and oregano. Cover with lime and lemon juice. Cover casserole dish with plastic wrap.

Combine the fish, onion, tomatoes, chili, salt, Tabasco, and oregano for the ceviche in a non-reactive dish
Stir:
Let sit covered in the refrigerator for an hour, then stir, making sure more of the fish gets exposed to the acidic lime and lemon juices. Let sit for several more hours, giving time for the flavors to blend.

During the marinating process, the fish will change from pinkish grey and translucent to whiter in color and opaque.

While marinating the ceviche, the fish will change from pinkish grey and translucent to whiter in color and opaque
Serve:
Serve with chopped cilantro and slices of avocado with heated tortillas for ceviche tacos or with tortilla chips.