Cook the Spaghetti: Cook the spaghetti according to the package instructions.
Prepare the Vegetables and Cheese: While the spaghetti is cooking, cut the small tomatoes into halves and slice the mozzarella into small pieces. Wash the salad thoroughly, dry them, and chop into bite-sized pieces. Peel the garlic clove.
Toast the Pine Nuts: Toast the pine nuts in a dry non-stick skillet over medium heat. Keep them moving constantly in the pan to prevent burning. Toast until they are golden brown.
Mixing: Once the spaghetti is cooked, drain and rinse with cold water for a few seconds. Transfer the spaghetti to a large salad bowl. Add the pesto rosso and pressed garlic, and mix well.
Combine All Ingredients: Add the toasted pine nuts, chopped tomatoes, mozzarella, and salad greens to the bowl. Toss everything together until well combined.
Serve: The spaghetti salad can be served immediately or stored in the refrigerator, covered well, to chill.