1) Blend all the ingredients, except the tuna, in a food processor until smooth but still chunky. Transfer to a medium serving bowl.
2) Drain the tuna but do not rinse. Flake the tuna with a fork. Add to the olive mixture, blending gently with a fork. Season with salt and pepper, to taste. Serve with crostini.
For the crostini:
Preheat the oven to 180C/Gas 4.
1) Slice the baguette, on the bias, into thin slices. In a small bowl, mix the oils and salt and pepper, to taste. Using a pastry brush, lightly coat one side of bread slices with the oil. Arrange on a sheet tray and bake until golden brown, about 8 to 10 minutes.