Combine beef, pork, rice, bread crumbs, eggs, 1/2 cup onion, 2 minced garlic cloves, mint, cilantro, 1 teaspoon salt, pepper, cumin, oregano, and red pepper in a large bowl. Using your hands, mix the ingredients together and roll the meat into golf ball size meatballs.
Stir in the tomatoes and simmer for an additional 5 minutes.
Lay the meatballs on top of the tomatoes and gently pour the chicken broth over them, being careful not to break the meat apart. Lower the heat to medium-low and simmer for 1 hour. Do not stir the meatballs while they are cooking.
Serve with toasted flour or corn tortillas and lime wedges.