Step 1 Combine the shrimp and one-third cup charmoula in a large nonreactive bowl or resealable plastic bag and marinate in the refrigerator for 2 hours. Ten minutes before removing the shrimp from the refrigerator, soak the bamboo skewers in water to prevent the wood from burning.
Step 2 Remove the shrimp from the marinade and thread with the lemon slices onto the prepared bamboo skewers.
Step 3Heat the grill over medium-high heat. When the grill is hot, oil the rack and place the skewers on top. Grill the skewers until the shrimp are puffy, pink and opaque, about 2 to 3 minutes per side. Serve immediately with the remaining charmoula sauce.