To blanch - place peas in a saucepan with just a few tablespoons of water and heat until the color turns bright green, about 3 minutes. Transfer the blanched peas with the other pesto ingredients into a blender or food processor. Whirl until pureed.
Preheat oven to 350.
To assemble Crostini, simply slice the bread, brush lightly with olive oil and place in the oven for just a few minutes until the bread feels lightly toasted, about 4 minutes.