1 In A Medium Bowl, Mix Together The Soy Sauce, Mirin Or Rice Vinegar, And Brown Sugar, Until The Sugar Is Completely Dissolved. Add The Fresh Ginger, Minced Green Onions, Chili Pepper Flakes, And Vegetable Oil. Place The Cubes Of Salmon In The Bowl, Coat Completely With The Marinade. Cover And Chill For 1 To 2 Hours. 2 Remove Salmon From Marinade. Place Marinade In A Small Sauce Pan And Bring To A Boil, Simmer For 10 Minutes, Set Aside. 3 Thread Salmon, Pineapple, And Onion Pieces On Skewers. If Using A Grill, Prepare Grill For High, Direct Heat. Oil The Grill Grates. Place Skewers On Grill. Cover. If Using An Oven Broiler, Place On A Rack On A Broiling Pan, So That The Salmon Pieces Are 6 Inches From The Element. Turn After 2 To 4 Minutes. Baste With Reserved Marinade. Cook For 2 To 4 Minutes More, Basting Frequently, Until Salmon Is Just Barely Cooked Through.