Whisk together the paprika, ancho powder, brown sugar, cumin, garlic, canola oil, salt and pepper in a small bowl.
Place the shrimp in a large bowl, add the spice rub and stir well to coat each shrimp.
Heat your grill to high.
Skewer 1/2 the shrimp and place on a grill pan to cook until just cooked through, 3 to 4 minutes. Stir in half of the green onions and transfer to a large platter or turnout onto brown paper bags. Wipe out the pan with paper towels, and repeat with the remaining ingredients.