Scoop the avocado into a medium bowl and stir, mashing with a fork or masher as needed, to get to a spreadable, somewhat chunky, texture.
Add the tahini, salt, garlic, and lemon juice and stir well to combine. Taste and adjust seasonings as needed. Transfer the mixture to a flat serving bowl or a plate and using the back of a spoon, make a well in the center. Drizzle with olive oil and dust with sesame seeds. Serve immediately.