Heat a large skillet over medium heat and add the sesame oil.
Add the onions and cook for about 2 minutes. Add the garlic and cook for an additional minute.
Add the ground beef, a pinch of salt and pepper, and cook, stirring frequently until cooked through, about 5 minutes.
Whisk the cornstarch in with the coconut aminos and add to the cooked beef. Cook for about 3 minutes to thicken.
Add the sesame seeds and green onion and stir.
Stir in the rice vinegar and let simmer for another 2-3 minutes to continue to thicken. Remove from the heat and set aside.
In a small bowl, whisk together the mayo and gochujang paste. Thin out with a little bit of water at a time until you reach the desired consistency.
Assemble the bowls with mixed greens, cauliflower rice, beef, gochujang mayo, and garnish with green onions and sesame seeds if desired.