Heat large nonstick skillet on medium heat. Add mustard seed; cook and stir 1 minute or until fragrant. Immediately pour out of hot pan to avoid over-toasting.
Coarsely crush seeds using a rolling pin or a mortar and pestle. Reserve 1 tablespoon for the Mustard Vinaigrette. Mix remaining mustard seed, vermouth, oil, lemon juice, honey, olive juice, lemon peel, sea salt, garlic and pepper in large bowl until well blended.
Reserve 1/4 cup of the marinade for brushing. Place remaining marinade in large resealable plastic bag or glass dish.
Add steak; turn to coat well. Refrigerate 2 hours or longer for extra flavor.
Meanwhile, bring water to boil in small saucepan. Add onions; cook 5 minutes. Drain well. Cool onions slightly. Cut off top and bottom ends, then peel onions. Remove steak from marinade. Discard remaining marinade.
Alternately thread steak, onions and olives onto 16 skewers. Grill kabobs over medium heat 8-10 minutes or until steak is desired doneness, turning occasionally and brushing with reserved marinade. Serve kabobs with Mixed Greens with Mustard Vinaigrette.