Cut the peppers into strips approx. 1 cm wide. Cut the white part of the onions into strips. Cut the green part of the onions into rings, set aside. Heat the oil and sauté the onion strips. Add the peppers and cook for about another 3 mins. Add the balsamic and water, cover and simmer for approx. 5 mins., season, then allow to cool a little.
Cut the baguette diagonally into slices approx. 1 cm thick, place the slices on a baking tray.
Toast for approx. 2 mins. in the top third of an oven preheated to 240°C. Halve the clove of garlic and rub the two pieces into the top side of the baguette slices.
Top the slices with the peppers and garnish with the reserved onion greens.