Heat oven to 400° F. Place the baguette slices on a baking sheet and brush both sides of the bread with 2 tablespoons oil. Bake until golden brown, 4 to 5 minutes per side
Heat the remaining tablespoon of oil in a large skillet over medium-high heat and add the mushrooms. Cook until tender, 4 to 5 minutes. Add the wine and simmer until the liquid has evaporated, 3 to 4 minutes; season with ¼ teaspoon each salt and pepper.
Dividing evenly, top the toasted baguette slices with the mushrooms and sprinkle with the chives.