Combine first 5 ingredients in a small bowl, stirring with a whisk. Add cranberries; let stand 5 minutes.
Spread about 1 teaspoon goat cheese on each bread slice. Arrange bread slices in a single layer on a baking sheet. Broil bread slices 1 minute.
Place 1 1/2 cups salad greens on each of 4 plates. Top each serving with 1 3/4 ounces trout and 1 1/2 teaspoons pistachios. Drizzle about 4 teaspoons dressing over each serving. Place 2 cheese toasts on each plate.