For the lemon vinaigrette: Using a rasp grater, grate the garlic into a bowl. Add the lemon juice, cumin, honey and Dijon. Whisk in the olive oil and season with salt and pepper.
For the 3-bean salad: Mix the celery, green onions, black beans, kidney beans and white beans in a large bowl.
Dress the salad with 1/4 cup of the vinaigrette and toss well. Season with salt and pepper and toss with the parsley.