Lay the prosciutto in a single layer on the prepared baking sheet and bake for 10 to 12 mins until crispy. Set aside to cool for 10 mins.
On another baking sheet, arrange the bread slices in a single layer. Using a pastry brush, brush the bread with 4 tbsp of the oil. Bake until golden, about 12 to 15 mins.
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 olive oil. Spoon the artichoke mixture onto the crostini. Crumble the prosciutto and sprinkle on top. Drizzle with oil and serve.