Place the arugula in a large bowl of cold water and gently agitate the leaves with your hands to remove any dirt or grit. Lift the leaves out of the water rather than pouring them through a strainer so sediment remains at the bottom of the bowl. Transfer the leaves to a salad spinner and spin until completely dry. If a spinner is unavailable, pat the leaves dry carefully with clean kitchen towels. Dry greens are essential for a well-balanced salad because moisture prevents the dressing from coating the leaves properly. Once dry, place the arugula in a large mixing bowl and keep it refrigerated while preparing the remaining ingredients.

Rinse the cherry tomatoes under cold running water and pat them dry. Slice each tomato in half lengthwise using a sharp knife. If the tomatoes are particularly large, quarter them so their size remains proportional to the arugula leaves. The goal is to create pieces small enough to distribute evenly throughout the salad. Set the prepared tomatoes aside.

Place the pine nuts in a small dry skillet set over medium heat. Toast them for 2–3 minutes, shaking the pan frequently so they brown evenly. Pine nuts toast quickly due to their high oil content, so monitor them closely and remove them from the heat as soon as they become lightly golden and fragrant. Transfer the toasted nuts immediately to a small plate to stop the cooking process and allow them to cool.

In a small bowl combine the olive oil, lemon juice, Dijon mustard, salt, and black pepper. Whisk the mixture vigorously for about 20 seconds until the dressing becomes lightly emulsified and smooth. The Dijon mustard helps stabilize the emulsion while adding subtle sharpness that complements the peppery arugula.

Remove the arugula from the refrigerator and drizzle the vinaigrette evenly over the leaves. Using salad tongs or clean hands, gently toss the greens until each leaf is lightly coated with dressing. Because arugula is delicate, mix carefully to avoid bruising the leaves.

Scatter the halved cherry tomatoes and toasted pine nuts over the dressed arugula. Toss very lightly once more so the ingredients distribute evenly without crushing the tomatoes.

Using a vegetable peeler or cheese knife, shave thin ribbons of Parmesan cheese directly over the salad. The large shavings provide bursts of salty, nutty flavor while maintaining an elegant presentation.

Transfer the finished salad to a serving bowl or individual plates and serve immediately. Arugula wilts quickly once dressed, so the salad should be enjoyed while the leaves remain crisp and vibrant.