Better ways to prepare bean burrito paste?

I would like to prepare the paste for Mexican-style bean burritos (preferably as delicious as possible and spicy). I've picked some beans at the supermarket, boiled them, fried them with some garlic, onions and hot peppers, and tried to mash everything with a fork and also tried to add some pepper and parsley but it just didn't turn out quite right. Any ideas why?

Thanks!!! :-)