Whisk together hoisin sauce, honey, soy sauce, minced garlic, grated ginger, vegetable oil, and rice vinegar in a medium bowl. The mixture should smell fragrant and sweet. Reserve half of this glaze in a separate container for basting during cooking.

Pat shrimp completely dry with paper towels - this ensures better browning on the grill. Toss shrimp with half the glaze mixture, making sure each piece is well-coated. Let marinate for 10 minutes while your grill heats up.

Thread marinated shrimp onto soaked wooden skewers, leaving small gaps between each piece for even cooking. You should have about 6-8 skewers depending on shrimp size. Preheat your grill to medium-high heat and oil the grates to prevent sticking.

Place skewers on the grill and cook for 2-3 minutes per side. Brush with reserved glaze during the last minute of cooking. Shrimp are done when they turn pink and opaque throughout - overcooking makes them rubbery, so watch carefully.

Remove from grill and immediately sprinkle with sliced green onions and sesame seeds. The residual heat will lightly toast the sesame seeds, releasing their nutty aroma.