A complete protein contains all 22 amino acids. One plant-based example of a complete protein is quinoa. However, proteins containing different amino acids can be eaten separately, even over a few days, and your body will still assimilate them as a whole source. Pretty neat stuff.
My protein sources include spirulina, nuts/nut butters, grains or beans. I tend to gravitate toward raw sources because they contain enzymes which aid in digestion, and the protein hasn't been denatured by heat. Processed food products such as tofu are actually not a part of my diet most of the time. Don't get me wrong, it's fine to have these types of foods in moderation, but the more processed a food is the harder your body works to digest it. You want a clean, plant-based, easily absorbable protein source that your body is instantly going to use to repair muscle tissue.
Spirulina, a type of algae, is instantly absorbable and raw, and contains over 50% protein! I throw it in my post-workout shake with coconut water (electrolytes) and some frozen or fresh fruit (carbs, and to mask the taste of algae).
So get out there and work it out...and refuel the clean, plant-based way!