Combine soaked beans, 6 cups water, onion, garlic, and bay leaf. Simmer gently for 60 to 75 minutes until tender. Add salt for the final 15 minutes and keep the beans in their broth.
Combine rice, 2 1/4 cups water, and salt. Bring to a boil, cover, reduce heat, and cook 15 minutes. Rest covered for 10 minutes, then fluff.
Cook the Chicharron:
Season pork belly with salt, pepper, and cumin. Heat oil in a heavy skillet, add pork, and cook over medium-low heat for 30 to 35 minutes, turning occasionally, until browned and tender with rendered fat layers. Drain briefly.
Assemble:
Mix tomatoes, red onion, cilantro, lime juice, jalapeno, and salt. Let stand 10 minutes.
Spoon rice and brothy beans into bowls and partly mix. Top loosely with pork, pico de gallo, and avocado. Add tortilla chips just before serving.
Notes
Keep enough bean broth to moisten the rice without turning the bowl soupy.
Store each component separately for up to three days and crisp the pork in a skillet before assembling leftovers.