Francis Lams Chinese American Thanksgiving Meatballs

Name: Francis Lam's Chinese American Thanksgiving Meatballs
Ingredients: 2 tablespoons vegetable oil; 1/4 pound stemmed fresh shiitake mushrooms, medium dice; 2 teaspoons Diamond Crystal kosher salt, plus more as needed; 1 bunch scallion, finely chopped; 2 tablespoons oyster sauce; 1 tablespoon sesame oil; 2 tablespoons sugar; 7 cloves garlic, very finely minced; 1/4 cup chicken stock; 1 pound ground turkey; 1/2 pound ground pork; Sauce; 3 tablespoons extra-virgin olive oil; 4 teaspoons peeled, finely minced ginger (from 1 1/2-inch piece); 1 (28-ounce) can diced tomatoes