In a bowl, add pork shoulder, pickle juice, and soy sauce and stir to coat meat. Cover with plastic film. Marinate in the refrigerator for about 30 minutes.
Drain pork well using a colander, reserving the marinade. In a wide pan over medium heat, add oil. Add chorizo de bilbao. Cook until lightly browned. Remove from pan and set aside.
In the same pan, add onion, garlic, and marinated pork. Cook until lightly browned, stirring occasionally.
Add tomatoes and cook, mash with the back of the spoon, until softened and release juice.
Add water, reserved marinade, tomato paste, sweet gherkin pickles, and bay leaf. Stir until distributed and bring to a boil.
Lower heat, cover, and simmer for about 20 to 30 minutes or until pork is tender.
Add pork liver. Let stand for about 20-30 seconds before stirring.
Add browned chorizo, bell peppers, and garbanzos. Stir well to combine.
Add salt and pepper to taste. Stir well.
Cover and cook for another 6 to 10 minutes or until sauce is thickened. Serve hot.