Preheat the oven to 400°F. Spray a small rimmed baking sheet with nonstick cooking spray and arrange the bresaola slices on the sheet. Arrange the bread slices on another baking sheet and brush the tops with the olive oil. Bake for 10 to 12 minutes, until the bresaola is crispy and the bread is lightly toasted.
Sprinkle the mozzarella over the bread slices and place in the oven for another 2 to 3 minutes, until melted. Top each crostini with a slice of bresaola, a few slices of persimmon, a drizzle of honey, and a sprinkle of fleur de sel.