quinoa is a "complete protein",

containing all the essential amino acids.

Other vegetarian food that's also rich with protein: beans, nuts, nut butter, tufo, egg. Just google "vegetarian food rich in protein".

Usually the recommended ratio of carb, protein and fat (the three macronutrients) is 3:1:1, and some recommendation is 50% carb, 25% protein and 25% fat. Generally people don't need worry about not taking in enough protein, including people on a vegetarian diet, because so many food sources are rich with protein.