1. Bring 2 qt. water to a boil in a Dutch oven; add shrimp, and cook 3 to 5 minutes or just until shrimp turn pink. Drain and rinse with cold water. Peel shrimp, leaving tails on; devein, if desired. Cut artichoke hearts in half.
2. Whisk together vinegar and next 6 ingredients in a large bowl. Pour mixture into a large zip-top plastic freezer bag; add shrimp, artichoke hearts, onion, and lemon, turning to coat. Seal and chill 4 hours, turning occasionally. Drain mixture, discarding marinade. Place in serving bowls. Garnish, if desired.
Marinated Lemon Shrimp With Olives: Prepare recipe as directed, substituting 1 (5 3/4-oz.) jar pimiento-stuffed Spanish olives, drained, for 1 (14-oz.) can artichoke hearts. Omit garnish.