1. In a large frying pan, brown meat over medium heat. Once cooked through, mix in the BBQ sauce. Remove the meat and set aside.
2. Returning the frying pan over medium high heat, add one tablespoon oil and onion. Cook, stirring continuously, until brown (about eight to 10 minutes).
3. Mix together the mayo, dijon mustard, lemon juice, salt, garlic and water.
4. To plate as shown in picture: On a large platter, spread the lettuce so it covers the whole platter. Top with a line of avocado, then the meat, then the tomatoes, then the onions, and finally the pickles. Drizzle with garlic mayo. You can also just place it all in one bowl and mix.