Does it have to be a snack, or can it be an easy meal? I am not clear if you are talking 'easy meal replacement' or an easy between meals snack, so forgive me if I am no help whatsoever...
I know you mentioned you don't want to even toast bread, but if I could persuade you to fire up the old micro or toaster, I'd have lots of ideas for you.
How about making a big bowl of hummus and eating it throughout the day/week with crackers? Or black bean dip with low fat chips? Add a piece of fruit and it's really a complete and filling meal/snack.
Or you could bake a few potatoes and make a pot of vegan chili with lots of vegs and tofu in it. Store them in the fridge, and when you are hungry nuke a potato covered in chili?
I really love baked sweet potatoes with bbq black beans - same principle as above, bake a few potatoes ahead of time and make a pot of black beans to last throughout the week.
There is always nut butter with whole grain crackers and fruit.
Vegan Vittles (great cookbook!) has a delicious recipe for chickpeas ala king that tastes great on whole grain toast. You could whip up a pot of that and when hungry nuke it and put it on a piece of toast.
You could always make or buy alot of veg. sushi and eat that when hungry.
Pasta salad? Rice salad? Any kind of grain and tofu salad?
How about greek salad? Assemble the greens and veggies, have the tofu feta substitute and olives in a separate container and the dressing also seperate and assemble as needed?
I hope these all haven't been too labor intensive for you, but I am really having a hard time thinking of foods that require no preparation or cooking at all. How about baked tofu, vegan lunch 'meats', nuts, seeds, dried fruits, and of course, soy yogurt? That's about the extent of what I can come up with!
I hope I helped!