Preheat the oven to 500°F (260°C). Line a baking sheet with a Silpat or parchment paper and spread out the pizza dough on it.
Spread the salsa evenly over the dough, leaving a small border for the crust, then sprinkle the grated mozzarella over the salsa.
Heat the olive oil in a large skillet over medium-high heat. Add the sliced chicken and cook until beginning to brown, about 4–5 minutes.
Add the sliced onion, red pepper, and green pepper to the skillet with the chicken. Sprinkle the Mrs. Dash seasoning, ground cumin, and salt and pepper to taste; cook until vegetables are tender and chicken is cooked through, about 4–6 minutes more.
Spread the cooked chicken and vegetable fajita mixture evenly over the pizza topped with cheese.
Bake the pizza in the preheated oven for about 8–10 minutes, or until the crust is golden and the cheese is melted and bubbly.
While the pizza bakes, chop the lettuce, dice the tomato, slice the avocado, and chop the cilantro.
When the pizza is done, remove it from the oven and top with chopped lettuce, diced tomato, sliced avocado, and chopped cilantro. Dollop or drizzle the sour cream over the top, slice, and serve.