Prep the base: In a large bowl, mash the avocado with lemon juice until mostly smooth. Leave a few small chunks for texture if you like.
Flavor boost: Stir in Greek yogurt (or mayo), Dijon mustard, garlic powder, and a pinch of salt and pepper.
If you like a softer, silkier salad, add a drizzle of olive oil.
Add the mix-ins: Fold in the tuna, celery, red onion, cucumber, and herbs. Break up the tuna gently with a fork so it’s evenly distributed but not mushy.
Taste and adjust: Add more lemon juice, salt, pepper, or red pepper flakes to balance the flavors. It should taste bright, creamy, and well-seasoned.
Serve your way: Spoon onto toast, tuck into lettuce wraps, pile over a salad, or scoop with crackers.
For a heartier meal, add sliced tomato or a jammy egg on top.