Wrap the pork tenderloin with plastic wrap and place in freezer for about 40 minutes. This will allow to you to slice the meat thinly.
Meanwhile, in a large re-sealable plastic storage bag or glass bowl, combine the pepper, sprouts, leeks, jalapeno, chili paste, vinegar, soy sauce, honey and oil and whisk well.
Remove pork from freezer and thinly slice the pork to about 1/4 in. thick, 1/4 in. wide and 2 1/2 in. long. Add pork to the plastic storage bag/bowl and marinate 1 hour in the refrigerator.
Wash and dry the hearts of romaine and separate the leaves. Place the romaine cups around the edge of a platter and set aside.
To ensure proper cooking, remove your prepared ingredients from the refrigerator approximately 10 minutes prior to cooking to take the chill off the ingredients.
Preheat a 9-in. stir fry pan or wok. When the rim of the pan is hot to the touch, add 1/3 of your ingredients and stir fry. When the meat has changed color and is fully cooked, place the cooked food in the middle of the platter with the romaine. Continue with the remaining meat mixture.
To serve, place some of the meat mixture into the romaine cups and sprinkle with chopped nuts.