Cover snow peas in water and 1 teaspoon salt in a large pot. Bring to a boil over medium-high heat and blanche peas for 5 minutes. Drain and then plunge into a bowl of ice water. This will stop the cooking process and intensify the color. Drain peas of water.
Whisk together orange juice, lime juice, olive oil, soy sauce, ginger, sesame oil, salt and pepper in a large bowl. Stir in peas and cooked shrimp. Cover and chill.
For transport to the picnic, pour off excess marinade and place shrimp and snow peas in a container with an airtight lid. Keep chilled until ready to serve.