1. Place eggs in a saucepan; add cold water to cover. Bring to a boil; remove from heat, cover, and let stand 12 minutes. Run eggs under water to cool; peel eggs, cut in half, and reserve.
2. Meanwhile, bring a large pot of water to a boil with 1 teaspoon salt; place a large bowl of ice water near stove. Boil asparagus 2 minutes or until bright green. Transfer asparagus immediately to ice water (reserve boiling water). Reserve ice water and repeat with snap peas, boiling 1-2 minutes. Drain and pat dry.
3. In a bowl, combine garlic, lemon zest and juice, vinegar, oil, remaining 1/4 teaspoon salt, and black pepper. In a serving bowl, combine asparagus, peas, watercress, herbs, and eggs. Just before serving, drizzle salad with dressing and toss to combine.