Combine first 6 ingredients in a shallow dish. Add asparagus. Toss to coat; let stand 20 minutes at room temperature.Preheat grill to medium-high.

Thread asparagus evenly on 4 double-pronged skewers, leaving space in between to allow air to circulate. Grill 3-5 minutes, turning once, or until asparagus are tender and charred in spots. Sprinkle with flake sea salt, if desired.