Preheat an indoor grill pan or outdoor grill to high. To cook the shrimp in the oven, preheat the broiler. If broiling, line a sheet pan with foil and coat with nonstick spray.
In a large mixing bowl, stir together the seasoning ingredients: garlic powder, salt, Italian seasoning, and cayenne. Drizzle in the olive oil and lemon juice and stir into a paste.
Add the shrimp and toss to coat. If using smaller shrimp, thread them on metal skewers or wooden skewers that have been soaked in water for at least 1 hour. Brush the grill or grill pan with canola oil. Grill or broil the shrimp, just until pink and opaque, about 2 to 3 minutes per side, turning once half way through (discard the extra liquid/spices that is left at the bottom of the bowl). Serve immediately.
