Preheat your grill to medium heat, approximately 350°F to 400°F.

Using a mandoline slicer or a sharp chef's knife, cut the zucchini and yellow squash into 1/8 inch thick ribbons.

Toss the sliced zucchini and yellow squash ribbons with olive oil, lemon juice, and salt until evenly coated.

Thread the marinated vegetable ribbons onto skewers, alternating with optional additional vegetables.

Place the skewers on the preheated grill and cook for about 12 minutes, turning occasionally.

Sprinkle freshly grated parmesan cheese over the skewers while still warm, and garnish with fresh herbs.