- Crush the garlic. In a blender or food processor, pulse the parsley, garlic, crushed red pepper and olive oil to a thick puree. Season with salt and pepper and transfer to a bowl.
- Cut the fish into 1 inch cubes. Thinly slice the zucchini lenghtwise on a mandoline and cut the shallot into small wedges.
- Onto each of the skewers, alternately thread a piece of fish, a slice of zucchini, and shallot repeating until each skewer has 3 pieces of fish, 3 slices of zucchini and 2 pieces of shallot.
- Season the skewers with salt and pepper and brush all over with the parsley sauce. Cover and refrigerate for 1 hour.
- Light a grill or preheat a grill pan. Grill the skewers over moderate heat, turning, until the fish is lightly browned and cooked through, about 6 minutes. Transfer to a platter. Meanwhile, half the lemon crosswise and grill them cut side down, until charred, about 2 minutes.
- Serve the skewers with the grilled lemon.