Combine aminos, vinegar, ketchup and set aside.
Slice steak against the grain into 1” thick strips and sprinkle with half a tsp salt and half a tsp black pepper.
Heat three tbsp olive oil in a skillet over medium-high heat.
Add beef and saute for approximately 5 minutes.
Add onion, bell peppers and saute for an extra 2 minutes, add sauce and mix.
Divide filling into three containers and pack up two lettuce leaves per container, when ready to eat, scoop filling into lettuce and roll-up.