Greek Meatball Hero

Name: Greek Meatball Hero
Ingredients: 1 cup breadcrumbs; 1 cup milk; 2 pounds ground beef; 1 cup crumbled feta; 1/2 cup grated Parmesan; 1 tablespoon dried oregano; 1 teaspoon salt; 1 teaspoon ground black pepper; 4 cloves garlic, finely chopped; 2 eggs; 2 plum tomatoes, diced; 1 English cucumber, diced; 1 red onion, thinly sliced; 3 tablespoons fresh parsley leaves, finely chopped; 3 tablespoons olive oil; 2 tablespoons lemon juice; Salt; 4 hero rolls; 8 ounces homemade or store-bought tzatziki