Make the marinade. Whisk together the lime juice, orange juice, EVOO, miso paste, and dulse flakes. It will take some vigorous whisking to break up the miso paste (it’s easier to do so if the miso is at room temperature).
In a large mixing bowl, mix together the sliced hearts of palm, chickpeas, tomatoes, red onion, jalapeño peppers, cucumber, and cilantro.
Pour the marinade over the hearts of palm salad and stir to evenly coat. Season with the salt and pepper, taste the salad, and adjust the seasonings accordingly. Cover the bowl and marinate in the fridge for at least 1 hour.