Bring a pot of water to boil. Insert a steamer attachment. Steam the tempeh for 10 minutes. Mix the tempeh with the carrot, celery and green onions (if using) in a medium sized mixing bowl.
Whisk together the mayonnaise or tahini, mustard, tamari, vinegar, and curry if desired. Pour over the tempeh and veggies. Mix well. Serve over toast, salad, grains, in a pita, or in a wrap. Leftover tempeh salad will keep for up to three days in an airtight container in the fridge.