Yes you can microwave Linguica and it will be safe to eat although when microwaving linguica it won't turn out as good as it would if you either grilled it or cooked it in the oven or on the stove.
To microwave linguica you put in in a microwave safe dish or on a microwave safe plate etc and then cook the linguica on high power for 5 minutes.
Cooking the linguica on the stove takes around 3 to 4 minutes and cooking the linguica on the grill takes around 10 minutes with 5 minutes on each side.
In the oven cooking the linguica takes around 20 minutes.
I prefer to either cook the linguica in the oven or on the stove or the grill and that goes for other sausages but you can microwave them to cook them if you want too.
Raw linguica will keep for up to 3 to 4 days in the fridge.
Just like other raw sausage the raw linguica will keep okay and safe in the fridge for up to 4 days and after 4 days the linguica or any other sausage should be thrown out.
The fridge will not keep the linguica or other sausage cold enough to keep bacteria from growing on it after 4 days.
If you want to keep the linguica or other raw sausage or any other raw meat longer than 3 days you should really freeze it instead.
When frozen the raw linguica or other sausage or any other meats will keep for up to 12 months or longer.
The freezer temperatures keep the bacteria from growing on the raw linguica or other raw meats or sausages.
For cooked linguica or other cooked sausage it will usually last for 7 days in the refrigerator and up to a year or more in the freezer.