Prepare the lima beans: The night before making this dish, soak two cups of dry lima beans in a large bowl of water. They will expand, so be sure to give them a lot of water and space. Rinse and strain the beans in the morning.

Wash the rice thoroughly and let it drain in a strainer until mostly dry. Heat 1 tablespoon of vegetable oil in a pan over medium heat, then add 1 teaspoon of freshly chopped garlic and 1 teaspoon of salt, stirring constantly to prevent the garlic from burning. Add the raw rice and stir well to coat it evenly with the garlic and oil, cooking until the garlic turns golden. Pour in 2 cups of water, stir a few times to prevent sticking, and cover the pot. Bring the water to a boil, then immediately reduce the heat to low and cook for approximately 8 more minutes. Turn off the heat, fluff the rice gently with a fork, and set aside to cool.

Cook the lima beans: In a skillet, heat 1 tablespoon vegetable oil and saute the onion, garlic, and ½ teaspoon salt over medium heat for 5-7 minutes. Add in the lima beans and cook for another 4 minutes. Pour in 4 cups of water or enough to cover the mixture by two inches. Simmer until the water has reduced and the beans have fallen apart, about 1 hour. Remove the pot from the stove, strain and then mash the lima beans. Allow to cool to room temperature.

In a large bowl, combine the cooked rice, lima beans, flour, 1 teaspoon of salt, and aji (if using). The mixture should be thick and hold its shape when formed.

In a skillet, heat 4 tablespoons of vegetable oil and heat over medium. Scoop about ¼ cup of the mixture into your hand and shape it into a round, flat cake with a 3-inch diameter. Fry each cake utnil golden brown and crispy, about 3 minutes per side.

Make the salsa criolla: Slice the onion in half and then thinly slice crosswise. Soak onion in a bowl of water with ½ teaspoon of salt for 10 minutes. Strain and pat dry. Mix in the chopped cilantro, lime juice, sliced peppers and 1 teaspoon salt, and ⅛ teaspoon pepper. Mix in ¼ teaspoon aji, if using.

Serve hot with fresh salsa criolla.