Preheat oven to 350°.
Place oats in a food processor; process until finely ground. Place ground oats in a large bowl. Lightly spoon flour into dry measuring cups; level with a knife. Add flour, sugar, baking powder, salt, and ginger to oats; stir well with a whisk. Combine 2 tablespoons water and eggs; stir with a whisk. Add egg mixture to oat mixture, and stir well. Stir in pecans.
Turn dough out onto a lightly floured surface; knead lightly 7 times. Shape dough into 2 (8-inch-long) rolls. Place rolls 3 inches apart on a baking sheet coated with cooking spray; pat to 1-inch thickness. Bake at 350° for 30 minutes. Remove rolls from baking sheet; cool 10 minutes on a wire rack.
Reduce oven temperature to 325°.
Cut each of the rolls diagonally into 10 slices. Place, cut sides down, on baking sheet. Bake at 325° for 10 minutes. Turn cookies over; bake an additional 10 minutes (cookies will harden as they cool). Remove from baking sheet; cool completely on wire rack.
Combine chips and oil in a small microwave-safe bowl. Microwave at HIGH 30 seconds or until chips melt; stir gently. Drizzle over biscotti.