Preheat the griddle at medium heat. If using a thermometer, you'll want it at about 375-400°f.
While griddle is preheating, combine all the sauce ingredients in a small bowl and whisk to dissolve the sugar.
When the griddle is hot, drizzle a little avocado oil and add the ground beef. Let it cook undisturbed for a couple of minutes, then flip and start breaking it up with your spatula. Cook until most of the pink is gone, which should take about 5-7 minutes total.
Pour the sauce over the ground beef and toss to combine. Cook for about a minute or two to thicken the sauce sauce slightly and to soften the onions.
Serve in lettuce wraps. Top with extra cilantro or green onions if desired.
Notes
Can serve these over rice. Substitute ground chicken or turkey for an even lighter meal!