Prepare the red beans: In a large saucepan, heat 2 tablespoons vegetable oil over medium heat. Add diced onions and minced garlic, sautéing until softened and fragrant, about 4 minutes.

Add the red beans (drained and rinsed if using canned), cumin, paprika, salt, and black pepper. Pour in 1 cup water or bean cooking liquid. Simmer for 15-20 minutes, stirring occasionally, until beans are creamy and flavors meld. Mash some beans against the side of the pan for a thicker consistency.

While beans simmer, prepare the pork: Cut pork belly into 1-inch cubes. Heat remaining vegetable oil in a large skillet over medium-high heat. Add pork cubes in a single layer, ensuring they don't overcrowd the pan.

Fry pork for 12-15 minutes, turning occasionally, until all sides are golden brown and crispy. Remove with a slotted spoon and drain on paper towels. Season lightly with salt.

Prepare pico de gallo: Dice tomatoes, remove seeds. Finely chop cilantro. Dice remaining onion. Combine tomatoes, onion, cilantro, lime juice, and a pinch of salt in a bowl. Mix well and set aside.

Slice avocados in half, remove pits, and slice into thin wedges.

To assemble: Divide warm beans among four serving bowls. Top each with crispy pork pieces, generous spoonfuls of pico de gallo, and avocado slices. Serve immediately with tortilla chips on the side.