Put an oven rack in the center of the oven. Preheat the oven to 375 degrees F. Spray a baking sheet with vegetable cooking spray
Lay the prosciutto in a single layer on the prepared baking sheet and bake for 10 to 12 minutes until crispy. Set aside to cool for 10 minutes.
On another baking sheet, arrange the bread slices in a single layer. Using a pastry brush, brush the bread with 1/4 cup of the oil. Bake until golden, about 12 to 15 minutes.
In a food processor, combine the artichoke hearts, beans, cheese, basil, lemon zest, lemon juice, salt, and pepper. Pulse until the mixture is chunky. With the machine running, slowly add the remaining 1/4 cup of olive oil. Spoon the artichoke mixture onto the crostini. Crumble the prosciutto and sprinkle on top. Drizzle with oil and serve.