Place 1/4 cup of dry bulgur in a bowl and cover the grains with warm water by about a 1/2 inch. Let them soak for 20 minutes; the bulgur will become tender. Drain the grains through a cheesecloth-lined strainer, and press the bulgur against the strainer to squeeze out excess water.
Transfer the bulgur to a large bowl. Add the finely chopped parsley and mint, as well as the garlic, lemon juice, tomatoes, cucumbers, scallions, and salt. Toss thoroughly to evenly distribute all of the ingredients.
Leave the tabbouleh out on the counter at room temperature or in the fridge for 2 hours. In this time, the bulgur will soak up the lemon juice and flavors and it will continue to plump up. After 2 hours, add the olive oil and toss to coat. Taste, and season with salt as needed.