MEATBALLS: Combine all the meatball ingredients, except the oil, and mix well. Form into 1 1/2-inch balls. Brown the meatballs in the oil, remove, and keep warm.
SAUCE: To make the sauce, add the oil to the pan and saute the onion and garlic until soft. Add the remaining sauce ingredients, bring to a boil, reduce the heat, and simmer for 15 to 20 minutes until the sauce is thickened. Place the sauce in a blender or food processor and puree until smooth. Return the sauce to the pan, add the meatballs, and heat through.
TORTILLA CUPS: To make the tortilla cups, pour the oil to a depth of 3 inches and heat to 375 degrees. Place a tortilla in the oil and let it float for a couple of seconds. Press the center into the oil with a can or ladle to form a bowl and fry until crisp, remove, and drain.
To serve, place the lettuce in each of the tortilla cups, top with the albondigas, and serve.