In a large skillet over medium heat, heat the olive oil. Add the chicken, onion, bell peppers, garlic, cumin, paprika, and chili powder and cook for 5-7 minutes, or until the chicken is cooked through.

Stir in the chicken broth and tomato paste and bring to a boil. Reduce the heat to low and simmer for 10 minutes. Season with salt and pepper.

Spread the refried beans on the tostadas and top with the chicken tinga mixture. Sprinkle with the queso fresco and any optional toppings. Serve hot. Enjoy!