In small bowl, whisk together mustard, vinegar, soy sauce, honey, rosemary, paprika, garlic, salt, pepper and cayenne pepper. Cover and let stand at room temperature for at least 1 hour to blend flavors.
Trim meat if needed and cut into 1-1/2-inch pieces. Transfer to large bowl. Spoon half of mustard mixture over beef; toss gently to coat. Place in zipper plastic bag and marinate for least an hour in the refrigerator.
On 10-inch skewers, thread meat, leaving 1/4 inch between pieces. Preheat grill. Reduce heat to medium (on a gas grill). Place meat skewers on grill rack over heat.
Cover and grill 8-10 minutes or until meat reaches desired doneness, turning once and brushing with remaining mustard mixture halfway through grilling.