In medium skillet over medium heat crumble and cook sausage until brown. Cool. In large bowl, combine baking mix, cheddar cheese and cooked sausage. Stir in 5 or 6 Tbsp. water to form a dough. Pat out into a thin layer on a large baking sheet or pizza pan. Bake for 10 minutes or until light brown.
Spread crust with refried beans. Top with onions, tomato, cilantro and Mexican cheese. Bake for an additional 10 to 15 minutes or until cheese is melted.