Boil the macaroni in salted water until just tender, then drain.
Rinse pasta under cold water to cool, drain well, and toss with olive oil.
Whisk mayonnaise, yogurt, Dijon, lemon juice, relish, dill, garlic powder, salt, and pepper.
Flake the drained tuna with a fork so it mixes evenly.
Combine pasta, tuna, celery, red onion, and peas in a large bowl.
Pour in the dressing and fold gently until everything is coated.
Chill 20 minutes, then taste and adjust lemon, salt, or pepper before serving.