My favourite style of beans on toast goes something like this :-
Lightly toast the bread, ie. make sure it is turning brown but not yet quite done and cut up into 4 quarters. The beans should be slightly dry otherwise the gravy will make the toast pretty soggy. Spread a thick layer on the now-cooled slightly-done toast and drown it in cheese coupled with a liberal sprinkling of salt and pepper. The type of cheese is largely a matter of personal preference.
Pop this into a pre-heated oven and keep watch over the toast. A moment too long and the toast and beans will be reduced to an awful charcoal black with the taste to match. As soon as the cheese starts bubbling take it out of the oven and offload the entire slice onto a serving plate. If possible garnish it with deep-fried thinly sliced onions (should be brown and crispy) and serve immediately for some calorie-laden magic.
Baked beans on toast never tasted so good..
Note : the level of salt and pepper are largely dependent on the type of cheese used. If cooked for too long in the oven, the beans tend to get dry and burnt on the outside.