1. Bring a pot of salted water to a boil.
2. Add the drained rice and red beans to the boiling water and cook according to the rice package instructions.
3. Drain and let cool completely.
4. Peel and finely chop the onion.
5. Cut the cooked chicken breasts into small pieces.
6. Clean, pat dry, and finely chop the parsley.
7. Mix mayonnaise, lemon juice, salt, and pepper in a bowl.
8. Dilute with a little water, stirring well.
9. Pour all the ingredients into the bowl and mix.
10. Keep the rice salad refrigerated until serving.