Season chicken with salt and pepper. Place in medium bowl. Puree Achiote paste with orange juice in blender. Add to chicken. Toss to coat. Set aside.
Melt butter in large saucepan over medium heat. Add carrots and celery and sautJ 5 minutes. Add chicken and jalapeZo and sautJ 3 to 5 minutes. Gradually whisk in stock. Simmer until slightly thickened. Combine flour, baking powder and salt in large bowl. Whisk eggs in glass measuring cup. Add enough milk to measure 3/4 cup. Add chopped cilantro. Whisk to blend. Add to dry ingredients and stir until blended. Drop dumpling mixture by rounded tablespoonfuls into bowl of iced water. Using slotted spoon, transfer to chicken mixture. Add enough dumplings to cover top of stew. Cover and simmer until dumplings are firm to touch, turning occasionally, about 12 minutes. Ladle chicken and dumplings into bowls.