Beans don't "produce" protein, Kreeden, they're composed of it.
Protein, in turn, is composed of amino acids. Humans use 20 different amino acids, 9 of which we must get directly from food. The other 11 we can assemble metabolically.
Different foods have different percentages of amino acids. Most foods don't have an optimum mix -- they may be low in one or another. This is a problem, however, only if you're living on only a single food. With a varied diet amino acid excesses and deficits balance each other out.
You're body can only use a certain amount of protein. Eating more will not automatically be incorporated into big muscles -- it just gets broken down. Protein breakdown, by the way, can have metabolically deleterious effects if your intake is high.
As far as meat vs vegetable sources, if you're looking for really concentrated sources put down your burger and load up on something like broccoli or asparagus -- both have more protein, calorie for calorie, than beef. This myth that plants are protein deficient is just that -- pure myth.