Step 1 Place the bread crumbs in a small bowl and cover with water to soak.
Step 2 Remove any membrane from the monkfish and discard. Chop the monkfish into small pieces and place in a food processor; pulse a few times until the fish is coarsely ground, being careful not to over-process. Transfer to a large mixing bowl.
Step 3Squeeze the water from the breadcrumbs and add the breadcrumbs to the fish, along with the egg, parsley, the one-eighth cup chopped capers, 1 teaspoon salt and the black pepper. Mix the ingredients thoroughly with your hands and then form the mixture into balls, using about one-eighth cup for each meatball. Set on a tray, cover with plastic wrap and refrigerate. This makes about 30 meatballs.
Step 4Add the olive oil and the onions to a large saute pan over medium heat. Cook the onions until soft (turning the heat to low if they begin to brown), 5 to 7 minutes. Add the garlic and cook an additional 2 minutes. Add the can of tomatoes plus the juice, basil, one-half teaspoon salt, the olives, 1 tablespoon whole capers and the red pepper flakes. Bring to a simmer over high heat, then reduce to low, cover and cook for 30 minutes. Check the pan occasionally, stirring once or twice to make sure the sauce isn't sticking to the bottom of the pan.
Step 5After 30 minutes, add the meatballs to the sauce, arranging them on top of the sauce. Cover and continue to simmer for 30 more minutes.
Step 6Meanwhile, bring 6 quarts of water and the remaining 2 tablespoons of salt to a boil in a large pot. When the meatballs have cooked 30 minutes, take the pan off the heat and cook the pasta, and drain. Serve the meatballs and sauce over the spaghetti.