Heat oven to 425°F.
In 2-quart saucepan, heat water and rice to boiling.
Reduce heat; cover and cook 9 minutes.
Stir in celery, bell pepper and onion.
Heat to boiling.
Reduce heat; cover and cook about 6 minutes longer or until rice is tender and most of water is absorbed.
Set aside.
On lightly floured surface, roll out 1 pie crust with rolling pin until 12 inches in diameter.
Place crust in ungreased 9- or 10-inch deep-dish pie plate; gently press in bottom and up side of pie plate.
Do not stretch.
In large bowl, mix beans, tomatoes, tomato paste and 1 tablespoon Cajun seasoning.
Stir in rice mixture.
Spoon into crust-lined pie plate.
Top with second pie crust; seal edge and flute.
n small cup or bowl, stir together salt and ¼ teaspoon Cajun seasoning.
Brush top crust lightly with water; sprinkle evenly with seasoning mixture.
Cut several slits in top crust for steam to escape.
Bake 30 to 35 minutes or until crust is golden brown.