Place the bulgur in a large bowl.

Cover the bulgur with water by 3 inches and soak for 45 minutes.

Drain the bulgur and squeeze to remove excess water.

Dice the cucumbers small.

Dice the tomatoes.

Chop the fresh parsley leaves.

Finely chop the green onions.

Cut the yellow onions into small dice.

Mince the garlic.

In a large bowl, mix the diced cucumbers, tomatoes, chopped parsley, green onions, yellow onions, minced garlic, olive oil, lemon juice, salt, and ground black pepper together.

Stir the prepared bulgur into the cucumber mixture and toss to combine.

Refrigerate the tabbouleh for at least 5 hours before serving.