I always pay the premium for sushi grade fish just for the safety factor; I also prefer the firm white fishes to the oily fishes like mackerel or sardines. Cut the fish into into bite sized cubes (3/4" or so), and place in a non-reactive container like a large ziplock bag or plastic bowl. Next, the olive oil and juice from all the citrus fruit into the bag and use enough lime to totally cover the fish. As a side note, I often add the lime zest from 1/2 the limes as well. Add the slice onions, and garlic; I like a little more garlic. I finely mince the stems of the parsley and cilantro because they add a lot of flavor, and save the leaves for garnishing the plate. I use about 1/4 cup total of the herb stems, you might adjust to your taste. The choice of chiles (aji in Peruvian) is trickier proposition. Ideally you would use Aji Rocoto (chile manzano) or possibly Aji Amarillo (sorry it's the spanish page), but they are hard to find. I use a mix of 3-5 jalapeños and 1/2->1 habañero seeded and minced. Take special care when working with the habañero or you will be in for a world of hurt. Finally Salt and pepper to taste, probably 1 tablespoon of a nice sea salt or kosher salt, and about the same of fresh course ground pepper. Seal the bag or cover the bowl and place in the fridge for 3 hours, agitating the works to ensure the flavours all macerate. Strain and serve, this should be enough for 6-8 people.1kg Sushi Grade skinless Halibut (Lenguado), or Sea Bass (Corvina)Juice from 2 OrangesJuice from 2 LemonsJuice from 12-15 Limes1/8 cup Extra Virgin Olive Oil1 Large Red Onion, quartered and thinly sliced5-10 cloves garlic mincedAji Rocoto or Aji Amarillo or Jalapeño Chiles or Habañero ChilesFlat Leaf (Italian) ParsleyCilantroSalt and Pepper to Taste.
In Peru this would be served on a bed of butter lettuce with some sliced boiled potatoes or yams and corn on the cob.