Make guacamole using 2 avocados, juice of 1 lime, cilantro, salt and pepper to taste. Set aside.
In a large skillet add the olive oil, and chicken strip and cook over medium-high heat for about 3 minutes or until chicken is lightly browned and cooked through; stir and flip intermittently. Remove chicken from skillet (keep the oil and cooking juices in the pan) and set aside.
If necessary, add a bit more oil to the pan. Add the onions and sauté over medium heat for about 5 to 7 minutes, or until they begin to caramelize and soften; stir intermittently.
Add the peppers and sauté for about 5 minutes, or until they begin to soften; stir intermittently.
Mix ingredients for fajita mix and set aside.
Return chicken to skillet.
Add the water, fajita-seasoning mix, and cook for about 3 minutes, or until chicken is heated through; stir intermittently.
Create a bed of guacamole on Casa Mendosa Tortillas. Spoon fajita mixture on top of guacamole. Top with diced tomatoes.