Teriyaki Tofu Brochettes

• 2 zucchini
• 1 bell pepper (yellow)
• 1 onion (red)
• 500 gr pineapple (fresh)
• 475 gr yaki
• 80 ml pineapple juice
• 80 gr button mushrooms
• 80 gr mirin
• 75 gr tamari
• 30 ml sesame oil