Cut steak into 1 in. pieces. Whisk together oil, lemon juice, water, mustard, honey, oregano and pepper in lrg bowl; add beef, bell pepper and mushrooms, stirring to coat.
Alternately thread pieces of beef, bell pepper and mushrooms on each of four 12 in. skewers. Place kabobs on rack on grid over med. coals. Grill 8-11 min. Season with salt, if desired.
Serve with long grain and wild rice.
Servings: 4