In separate pots, boil the corn and the sweet potato until tender. Peel the sweet potato. Let both cool, then cut corn into 2-inch sections and potato into 1-inch sections.
Place cubed raw fish in a bowl with the garlic, coriander and chili pepper. Add enough lemon juice to cover the fish. Season with salt and pepper. Let marinate for 10 to 45 minutes, until the fish is milky white.
For each serving, place a mound of the fish on a leaf of lettuce. Top with onions and a ring of red pepper, and add corn and sweet potato.
2 ears of corn
1 large sweet potato
2 pounds of fresh sole or sea bass, cut into half-inch cubes
2 teaspoons crushed garlic
2 teaspoons chopped coriander
2 teaspoons spicy red chili pepper, chopped in a blender
Juice of 8 to 10 small lemons
Salt and pepper to taste
4 large leaves of lettuce
2 medium onions, thinly sliced
1 large hot red pepper, sliced into quarter-inch rings