1. In large saucepot, cook pasta in boiling salted water as label directs, adding frozen peas during last 2 minutes of cooking time. Drain pasta and peas; rinse with cold water and drain well.
2. Meanwhile, from lemons, grate 1 tablespoon peel and squeeze 3 tablespoons juice. In large bowl, with wire whisk, mix lemon peel and juice with milk, mayonnaise, pepper, basil, green onions, and 1 teaspoon salt until blended.
3. Add pasta and peas to mayonnaise dressing; toss to coat well. Cover and refrigerate up to two days if not serving right away.