Combine the EVOO, scallion whites, chile and lemon juice in a medium bowl and season with salt and pepper. Add the shrimp and toss to coat. Wrap each shrimp with a slice of prosciutto and thread onto a skewer.
Grill the shrimp until firm and opaque, about 3 minutes per side. Transfer to a serving platter and garnish with the scallion greens and another squeeze of lemon juice.