Dice chicken fillets, marinate in 3 tbsp soy sauce and 2 tbsp pineapple liquid for 1 hour.
Dice onion, cut leek into rings, peel tomatoes and cut into eighths, remove peel from garlic and press through a press, drain pineapple.
Except for the pineapple chunks, put everything into a microwave-safe dish (incl. marinating liquid). Cook covered at 600 watts for 6 minutes. Add pineapple and stir once, cook for another 6 minutes.
Stir 2 tbsp. soy sauce with cornstarch, add and cook for another 2 minutes (if the sauce is not enough, add a little more pineapple liquid).
Season with salt, pepper and maybe sugar and serve with long grain rice.
* Per person 235 calories (995 joules)