Place frozen peas in a bowl of warm water to thaw. Drain when thawed.
Cook macaroni, drain and rinse with cold water.
Place in a large bowl.
Add the drained tuna, celery, onion, and thawed peas.
Toss gently to mix.
In a small bowl whisk the mayonnaise, juice, and seasonings.
Add to the macaroni mixture and toss with a wooden spoon or rubber spatula.
Chill and serve.
Video
Notes
Don't be tempted to taste the salad before the chill. The dressing will have a tangy lemon flavor, but this will calm down during the marination in the fridge.