In a medium pot combine water, olive oil and a pinch of salt. Bring it to a boil, add stir in couscous, close the lid and remove from the heat.
In a medium bowl mash the avocado, add garlic, yogurt, 1 tablespoon vinegar, salt and pepper to taste. Mix the dressing until smooth and creamy. You may wish to stir in the remaining 1 tablespoon of vinegar.
Pull the dandelion leaves off from the tough stems and discard the stems. Use a knife to chop the leaves into bite-size pieces. Transfer the dandelion to a big salad bowl.
Fluff couscous with a fork and add it to a bowl with dandelion greens along with cucumber, bell pepper and green onion.
Pour the avocado dressing over the salad. Toss until the salad is coated with dressing. Serve immediately.