In medium pot, bring soy sauce, vinegar, water, sesame oil, ginger, and maple syrup to a boil. Remove from heat. Pour half into medium bowl and stir in peanut butter powder.
Return pot with remaining marinade to stove and add tempeh pieces. Reduce heat to medium-low, cover, and simmer for 10 minutes, turning tempeh frequently to braise evenly. Remove lid and cook until no liquid remains.
To assemble, place small amounts of tempeh and fillings in lettuce or collard leaves. Tuck in sides of leaves and roll up to seal, or leave open like tacos. Serve with peanut sauce.
Enjoy!