Blend all ingredients from mayonnaise to capers in a food processor or blender on high until smooth. Fold in basil, add salt and pepper to taste, and chill. Preheat oven to 350°. Brush baguette slices with a little rémoulade. Bake bread slices until golden brown on the edges but soft in the middle, about 7 to 8 minutes. Toss the chicken with ¾ cup of the rémoulade. Evenly distribute the chicken on top of each of the crostini. Garnish the crostini with a small dollop of basil rémoulade, and place remaining basil on top as a garnish. Extra rémoulade can be tossed with any remaining chicken for a zingy chicken salad.