To make vinaigrette: Whisk together lemon juice, zest and salt. Slowly pour in oil, and whisk until dressing is emulsified.
To make salad: Have large bowl of ice water ready. Bring large pot of salted water to a boil. Add peas and sugar snap peas, and boil 1 minute. Drain, and immediately dunk vegetables in ice-water bath. Drain well, and transfer to large bowl.
Add radishes and carrots to peas mixture; toss with 1/4 cup vinaigrette (reserve remaining vinagrette for another use.) Gently stir in pea shoots.
Per 1 cup serving: 135 cal; 4 gr protein; 7 gr total fat; 14 gr carbs; 0 mg cholesterol; 77 mg sodium; 5 gr fiber; 6 gr sugar.