Slice all of the ingredients and marinade the zucchini in the oil with garlic powder. You can marinade all of the vegetables but I like to keep the rest to a more natural flavor myself.
Heat up your hibachi grill with your binchotan charcoal, that would of course be ideal. But if you don't have those don't worry. You can also grill these on any type of grill, or melt the butter in a pan over medium heat level.
First add the sliced onion to the grill, make sure the slices are large enough not to fall through the grates (as with all of the vegetables of course). Heat them for about three minutes.
Add the other vegetables to the grill or pan for about four minutes each while the onion has been on the grill for three minutes. If you're using a pan or wok and are stir frying, make sure you fry them separately.
Finally, mix the grilled vegetables up in a bowl and add the soy sauce, teriyaki sauce and some salt and pepper to taste. I do like to keep the broccoli with a nice bite from the grill and will often times keep those separate from the mixing bowl and without sauce, just to give the dish more of a crunch.
Give it a final touch by sprinkling your sesame seeds on top.
Your vegetable Hibachi is ready.