Slice the tenderloin into 1/2-inch-thick slices and lightly pound each with the flat side of a meat pounder until about 1/4 inch thick. Each piece should be rectangular (about 1 1/2 by 2 1/2 inches); trim off any raggedy bits for another use, such as a stir-fry. Stir together sliced ginger, sliced garlic, spring onions, and olive oil in a bowl. Add beef, toss to coat, cover, and marinate in the refrigerator at least 8 hours.
Prepare a charcoal or gas grill for high heat (you can hold your hand at grill level only 2 to 3 seconds).
Meanwhile, whisk together grated ginger, grated garlic, rice vinegar, and soy sauce in a small bowl. Thread beef slices onto soaked skewers (see notes) and season with salt and pepper.
Brush the grill with vegetable oil. If using coals, mound to one side to reach about 4 inches below the grill. Lay skewers on grill; close lid on gas grill.
Grill skewers just until seared, turning once, about 30 seconds per side. Serve skewers drizzled with ginger sauce and garnished with chives.
Note: Nutritional analysis is per skewer.