Cooking Salmon in foil in your oven takes between 20 to 30 minutes depending on how well cooked you want the Salmon.
Salmon can be eaten raw so any amount of cooking time is good enough depending on how well done you like the Salmon.
I like mine pretty well done so I cook it for 30 minutes but usually 20 minutes is enough cooking time for some people.
Before wrapping the salmon in foil I like to spread some butter onto my salmon which makes it taste better and you can add some seasoning to it as well if you want too.