Combine first 7 ingredients in a large zip-top plastic bag; add beef to bag. Seal and marinate in refrigerator 4 to 6 hours, turning bag occasionally.
Combine mayonnaise, 2 teaspoons juice, wasabi, and 1/4 teaspoon garlic, stirring with a whisk. Refrigerate at least 1 hour.
Prepare grill to medium-high heat.
Remove beef from bag; discard marinade. Thread 5 beef cubes alternately with 4 tomatoes and 4 green onion pieces onto each of 4 (12-inch) skewers. Sprinkle salt evenly over kebabs. Place kebabs on grill rack coated with cooking spray; grill 4 minutes on each side or until desired degree of doneness. Serve with mayonnaise mixture.