2 tablespoons toasted sesame oil
2 tablespoons rice vinegar
1 tablespoon toasted sesame seeds
1 tablespoon granulated sugar
1 1/2 teaspoons soy sauce or tamari
1/2 teaspoon red-pepper flakes
2 ripe avocados
1 pound cucumbers (such as Persian or English), trimmed and thinly sliced
2 green, red or purple scallions, trimmed and thinly sliced
Kosher salt (such as Diamond Crystal) and black pepper
Toasted sesame seeds, for topping
Make the dressing:
Place the sesame oil, rice vinegar, sesame seeds, sugar, soy sauce and red-pepper flakes into a small bowl.
Add 1 tablespoon of water and whisk until emulsified. Taste, and adjust seasonings. (Dressing should taste acidic, a little sweet and salty.)
Prepare the salad:
Halve the avocados and discard the pits.
Using a small paring knife, carefully score the avocado flesh into 1/2-inch cubes, avoiding cutting through the skin.
Use a large spoon to scoop out the avocado flesh (in one spoonful, if possible), as close to the skin as possible. Transfer avocado cubes to a large bowl and add the dressing; toss gently.
Add the cucumbers and scallions and toss everything together.
Season with salt and black pepper, top with more sesame seeds, and serve immediately.