Make the dressing: Whisk together the lime juice, olive oil, salt, pepper, ginger, and oregano. Let this “ceviche juice” mixture stand for about 1 hour to allow all the great flavors to meld.

While the dressing is resting, prepare the rest of the ingredients: Put the onion slices into a sieve and very briefly rinse them in cold running water. Drain well. Mince the jalapeño peppers and cilantro leaves; stir together.

Drain the liquid from the can of hearts of palm. Cut small circles of palmito about ¼-inch wide. Mix the palmito pieces with the ceviche juice and soak for at least 10 minutes.

Serve your hearts of palm ceviche at room temperature on salad plates or bowls. Assemble each portion by spooning in part of the chopped palms, then some cilantro and with hot pepper, than a layer of onion slices; repeat layers. Moisten everything with a bit of ceviche juice. (Alternately, mix everything together, very gently, in a large bowl, then spoons portions onto salad plates.) Garnish each serving with a slice of lime or jalapeño and/or a little more cilantro, if desired.