Add 1 tablespoon (15 ml) of the olive oil to a cast-iron skillet. Turn the burner to medium and heat until shimmering. Add half of the onion and ½ teaspoon of the salt. Reduce the heat to medium-low. Sauté the onion for 12 to 15 minutes, stirring occasionally, until golden brown.
While the onion is cooking, add the remaining olive oil to a small saucepan. When shimmering, add the remaining onion and ½ teaspoon of the salt and sauté on medium-low for 12 to 15 minutes, stirring occasionally, until golden brown.
Add 1 tablespoon (9 g) of the garlic to each pan. Sauté for 1 to 2 minutes.
Add the tomato paste to the cast-iron skillet and increase the heat to medium. Sauté the tomato paste until it becomes a deep, rich red, 2 to 3 minutes. Add the bell peppers and continue to sauté until they become soft, about 5 minutes. Set aside.
Add the cumin to the saucepan and sauté until fragrant, 1 to 2 minutes. Add the beans and 1 cup (240 ml) of water. Simmer for 15 minutes or until the beans are soft and easily mashed with a fork.
Add the tomatoes to the pepper hash and top with two large spoonfuls of mashed white beans. Serve with fresh cilantro, if using, and fresh ground pepper. For fun, you can give the white beans the appearance of eggs by placing half of a yellow grape tomato in the center.