In a cup, combine salt, pepper and paprika; sprinkle on both sides of chicken.
In a large skillet over medium-high heat, heat oil until hot. Add chicken, green peppers, onion and garlic to skillet; cook, stirring frequently and turning chicken to brown on both sides, about 5 minutes. Remove chicken from skillet.
Add tomatoes and bouillon granules; cook uncovered, stirring until tomatoes are softened, about 10 minutes. Return chicken to skillet. Reduce heat to medium; cover and simmer until chicken is cooked through, 10 to 15 minutes.
Stir in piquillo peppers and olives and cook just until heated through, about 2 minutes. Serve over saffron rice, if desired.