To create a flavorful yet balanced “cooking” liquid for our Peruvian fish ceviche, we made what's known as a leche de tigre by blending lime juice, aji amarillo chile paste, garlic, extra-virgin olive oil, and a small amount of fish. Once strained, the liquid was an intensely flavorful and silky-textured emulsion. We then soaked thinly sliced and briefly salted fish (red snapper, sea bass, halibut, and grouper were all good options) in the leche for 30 to 40 minutes until it was just opaque and slightly firm. To complete the dish, we added sweet oranges; crisp, peppery radishes; and chopped cilantro. We served the ceviche with corn nuts and popcorn, which provided salty crunch.