Cook rice in 2 cups boiling water for 20 minutes. Meanwhile, cut chicken into bite-sized cubes. Combine flour with paprika and oregano. Dust chicken cubes with flour mix lightly, reserving remaining flour mixture. In a large deep skillet, melt half of the butter. Cook chicken until lightly browned. Remove and reserve.
Add remaining butter to pan. Add onions and garlic. Cook 3 minutes. Sprinkle on 2 tablespoons remaining flour. Cook 2 minutes. Stir in milk. Bring to a boil. Add chicken pieces and cook 8-10 minutes. Cut tomatoes into chunks. Drain and dice Feta cheese. Add tomatoes and cheese to chicken. Cook one minutes. Taste and adjust seasoning if necessary. Serve chicken over rice, sprinkle with olives.