Preheat gas grill for medium-high heat. Meanwhile, combine salmon, bread crumbs, Egg Beaters, mustard and pepper in medium bowl. Shape mixture into 6 patties, about 1/2-inch thick.
Spray 18x12-inch piece of heavy foil with grilling spray; place on grill grate. Add salmon patties; grill 4 minutes on each side or until set and hot. Meanwhile, spray cut sides of buns with grilling spray; toast on grill.
Spread mayonnaise evenly on cut sides of buns. Place patties on bottom halves of buns; top with tomato. Close with tops of buns.