Combine fish, juice, onion, cilantro, and jalapeño in a large bowl and gently fold with your hands to combine. Season to taste with salt and pepper. Allow to marinate for at least 5 minutes, folding occasionally. Transfer to a serving platter and serve immediately with boiled corn and sweet potatoes, if desired. This Recipe Appears In The Food Lab: How to Make the Best Ceviche Serious Entertaining: A Light, All-Chilled Spanish(ish) Menu
