Grilled wild Salmon Spinach Salad

1 (20 ounce) can pineapple slices 3 tablespoons soy sauce 1/2 teaspoon dry mustard 2 garlic cloves, minced 1 teaspoon ground ginger 1 tablespoon brown sugar, packed 1 lb wild salmon 2 tablespoons vinegar 2 tablespoons oil 6 cups fresh spinach, washed 4 -5 tablespoons...