Prepare gas or charcoal grill to medium-high heat for direct-heat cooking.
Toast coriander and cumin seeds in a small saute pan over medium heat for 2 minutes or until fragrant and lightly browned. Remove from pan, cool and grind.
Place ground spices in a large bowl; add cilantro, scallions, egg, kosher salt and 1/2 teaspoon pepper; mix well. Gently but thoroughly mix in salmon and panko. Shape mixture into 6 (3/4-inch thick) patties and refrigerate until ready to grill.
Curried Mustard Mayo: Heat canola oil in a very small nonstick saucepan over medium heat. Add ginger and garlic and saute for 2 minutes. Stir in curry powder and continue to saute for 1 minute. Remove mixture to a mini food processor; reserve pan. Add mayonnaise and mustard to processor and puree. Remove to a small bowl, stir in cilantro and season, to taste, with sea salt and pepper. Refrigerate until needed.
Orange-Apricot Glaze: Place preserves, butter, orange juice concentrate and cayenne in reserved saucepan and cook over medium heat, stirring, until preserves and butter have melted. Boil glaze for 2 minutes. Remove from heat and set aside.
Oil grill grates canola oil. Grill burgers over direct heat for 3 minutes, covered if using a gas grill. Gently flip burgers and grill for 3 minutes. Brush burgers with half of the glaze; flip and cook for 1 minute. Brush with remaining glaze; flip and cook for 1 additional minute or until burgers are cooked through. Remove. Spray cut sides of buns lightly with cooking spray and grill cut sides down, along outer edges of grill, until lightly toasted, about 1 minute.
Spread cut side of bottom buns with half of mayo mixture; top with half of the watercress leaves, a burger, remaining mayo, remaining watercress and tops of buns. Garnish platter or dinner plates with cilantro and watercress sprigs, as desired.
Recipe courtesy of Jamie Miller, Maple Grove, MN