Drain the canned tuna very well using the can lid to press out excess liquid until the tuna looks dry and flaky.
Transfer the tuna to a medium-sized mixing bowl and gently break it apart with a fork for your preferred texture.
In a small bowl, whisk together the mayonnaise, Dijon mustard, lemon juice, minced garlic, salt, and black pepper until smooth and creamy.
Add the chopped celery, red onion, dill pickles, fresh dill, and parsley to the tuna bowl.
Pour the dressing over the tuna mixture and gently fold everything together until evenly coated without overmixing.
Taste the tuna salad and adjust with extra lemon juice, salt, or pepper if needed for brightness and balance.
Cover and refrigerate the tuna salad for at least 30 minutes so the flavors can blend and the texture can firm up slightly.
Serve chilled on sandwiches, lettuce wraps, crackers, toast, or over salad greens.