Preheat the oven to 500°F (260°C). Line a baking sheet with a Silpat or parchment paper and stretch or roll the pizza dough to fit.
Heat the olive oil in a large skillet over medium-high heat.
Add the sliced chicken to the skillet and cook until beginning to brown, about 3–4 minutes.
Add the sliced onion, red and green peppers, Mrs. Dash seasoning, ground cumin, and salt and pepper; cook until the vegetables are tender and the chicken is cooked through, about 4–6 more minutes.
Spread the salsa evenly over the prepared dough, then sprinkle the grated mozzarella over the salsa.
Top the cheese with the cooked chicken and vegetable fajita mixture, spreading it into an even layer.
Bake the pizza in the preheated oven for about 8–10 minutes, or until the crust is golden brown and the cheese is melted.
While the pizza bakes, wash and prepare the cold toppings: chop the lettuce, dice the tomato, slice the avocado, and chop the cilantro.
Remove the pizza from the oven, top with lettuce, tomato, avocado, cilantro and dollops of sour cream, then slice and serve.