Preheat the oven to 400 degrees . Bring a large pot of water to a boil, salt it, add the linguine and cook until al dente, about 4 minutes. Drain.
While the pasta is working, in a medium bowl, beat together the eggs and milk. Season with a little salt and lots of pepper.
In a medium ovenproof skillet, heat 1 tablespoon EVOO, 1 turn of the pan, over medium heat. Add the pancetta and cook until crisp, 3 to 4 minutes. Add the garlic and cook for 1 minute. Add the drained pasta, a handful of parsley and 1/2 cup cheese; toss to combine. Pour the eggs over the linguine and cook until the eggs begin to set, 2 minutes. Bake in the oven for 10 minutes. Top with the remaining 1/2 cup cheese and bake until light golden, 3 to 4 minutes more.
In a bowl, combine the tomatoes, cucumber, onion and remaining handful of parsley. Toss the salad with the remaining 3 tablespoons EVOO and season with salt and pepper.
Cut the pasta frittata into 4 pieces and serve with the tomato-cucumber salad.