In a large pot of boiling water you’ll add a 12 ounce box of tricolor pasta and cook according to package instructions until slightly al dente, then drain and let cool for 5 to 10 minutes.
In a small bowl whisk together 1 cup garlic hummus, ⅓ cup milk, 1 teaspoon garlic powder, and ½ teaspoon salt until smooth, adding an extra tablespoon of milk if the mixture feels too thick.
Transfer cooled pasta to a large bowl, add 1 cup halved cherry tomatoes, 1 cup diced green bell pepper, 1 cup diced cucumber, and ½ cup diced red onion, then pour in the hummus dressing and stir until everything is evenly coated.
Cover and chill for at least 30 minutes before serving; if it firms up too much, stir in a tablespoon of milk at a time until it loosens to your liking.