Thaw shrimp, if frozen. Peel and devein shrimp. Bring 4 cups water to boiling in a medium saucepan. Add shrimp. Simmer, uncovered, for 1 to 3 minutes or till shrimp turn pink, stirring occasionally. Rinse under cold running water; drain. Set aside. Combine garlic, lime peel, limejuice, olive oil, onion, anaheim pepper, cilantro or parsley, sugar, salt, and pepper in a heavy plastic bag set in a medium bowl. Place cooked shrimp in bag. Turn bag to coat shrimp with marinade mixture. Marinate in the refrigerator for 2 to 3 hours, turning bag occasionally. To serve, drain shrimp, discarding the marinade.