Smoked Salmon and Potato Frittata

Name: Smoked Salmon and Potato Frittata
Ingredients: 4 ounces cream cheese , cut into ½-inch pieces, divided; ¼ cup water; 10 large eggs; 3/8 teaspoon table salt , divided; ½ red onion , sliced thin; 2 tablespoons lemon juice; 1/4 cup extra-virgin olive oil , divided; 2 cups frozen diced hash brown potatoes; 4 ounces smoked salmon , chopped; 2½ teaspoon everything bagel seasoning; 2 plum tomatoes , cored, halved lengthwise, and sliced crosswise ¼ inch thick; ½ cup coarsely chopped fresh dill