In a mixing bowl, combine olive oil, chopped parsley, minced garlic (if using), lemon zest, and salt and pepper. Whisk until well-blended. Add shrimp to the marinade and let it marinate for 15 minutes.

Preheat your grill to medium-high heat, around 400°F (205°C). Prepare corn and bell peppers by cutting the peppers into strips.

Grill the marinated shrimp on skewers or grates for 3-4 minutes per side. Grill corn for 8 minutes, and bell peppers for 5-7 minutes until tender.

Create a bed of grilled romaine in a large serving plate. Grill the romaine cut-side down for 1-2 minutes.

Layer the grilled shrimp on top of the salad base. Add grilled corn, grape tomatoes, and diced cucumber. If using, slice and arrange avocado on top.

In a small bowl, whisk honey, mustard, and white wine vinegar. Gradually add olive oil while whisking until smooth.

Drizzle the vinaigrette over the salad just before serving to combine flavors and enjoy.