In a medium bowl, mash the avocados with a fork until mostly smooth, leaving a few chunks for texture.
Add the Greek yogurt to the mashed avocado and stir gently to combine.
Fold in the diced cucumber, crumbled feta, minced garlic, lemon zest, lemon juice, dill, mint, and oregano. Drizzle in the olive oil.
Taste the spread and season with salt and pepper. Adjust the lemon juice if you want it tangier.
Spoon the spread into a serving bowl. Garnish with extra dill, a drizzle of olive oil, and (if using) chopped kalamata olives.
Serve immediately with warm pita bread, fresh veggies, or as a topping for grilled chicken, lamb, or fish.