Preheat oven to 400F.
Lightly grease a 13x9 baking dish and set aside.
In a large nonstick skillet, heat the olive oil.
Add onions and cook for 4 minutes, or until softened.
Stir in garlic and cook for 30 seconds, or until fragrant.
Add shredded pork and season with cumin; continue to cook for 8 minutes, or until heated through.
Remove from heat.
Warm the tortillas in the microwave for about 30 seconds so that they're easier to roll.
Add pork mixture to each tortilla and roll it up tightly.
Transfer prepared tortillas to the previously prepared baking dish, seam-side down.
Lightly spray the tops of the rolled up tortillas with baking spray.
Bake for 13 to 15 minutes, or until tops are lightly browned.
In the meantime, prepare the Avocado Crema.
Place all of the ingredients in the bowl of a food processor; process until smooth, stopping and scraping down the sides of the bowl with a rubber spatula as needed.
Transfer the crema to a small bowl and set aside.
Layer the shredded romaine lettuce on a large platter.
Arrange the prepared flautas over the lettuce.
Top flautas with chopped tomatoes and serve with a side of the prepared Avocado Crema.