Sweet And Sour Tuna

• 2 tomatoes
• 2 cans tuna in oil
• 1 rice (hot cooked)
• 270 gr pineapple tidbits
• 120 ml vinegar
• 50 gr sugar
• 16 gr cornstarch
• 16 ml soy sauce
• 4 slices green onions
• 1 slice green pepper (sliced thin)