Soak one pound of pallares (large lima beans) overnight or at least 6 hours. Change water two or three times.
Boil the beans (without salt) with enough water to cover them. Use high heat until water reaches boiling point. Skim and reduce your fire. Simmer for about 1 hour. No exact timing is possible, since cooking time depends on the dryness of the beans.
When the beans are plump and tender, take them off the heat and drain. You might reserve the boiling liquid to process leftovers into a soup.
Season the beans lightly with salt (kosher works great) and, while the beans cool down, prepare your vinaigrette.
Mix one cup of olive oil, two or three spoonfuls of white vinegar, one spoonful of Dijon mustard, salt and pepper to taste, one finely diced small red onion, and two diced seeded tomatoes.
About half to one hour later, once the beans are at room temperature, check the seasoning of the vinaigrette. It should taste a bit stronger than expected.
Carefully mix the vinaigrette with the beans. Finely cut a few sprigs of parsley and mix again.
Reserve some more parsley for decoration, and voila!