Preheat the broiler. In a medium bowl, beat the eggs with 1/2 teaspoon of the salt and the black pepper; set aside.
In a medium bowl, combine the pork, Italian seasoning, paprika, fennel seeds, red pepper flakes, and remaining 1/4 teaspoon salt; mix well.
Heat the olive oil in a large oven-safe skillet over medium heat. Add the pork mixture and cook, stirring frequently, until the meat is browned. Add the mushrooms and garlic.
Cook, stirring, until the mushrooms are tender, 3 to 4 minutes. Stir in the arugula and cook until wilted, about 1 minute. Pour the egg mixture into the skillet. As the mixture sets, run a spatula around the edge of the skillet, lifting the egg mixture so the uncooked egg flows underneath. Cook until almost set, 2 to 3 minutes more.
Place the skillet under the broiler, 4 to 6 inches from the heat, and broil for 1 to 2 minutes, until the top is set.
To serve, top the frittata with the tomato and green onions. Cut into quarters and serve hot, directly from the skillet. Pass hot sauce alongside, if desired.