Combine first 7 ingredients in a large stockpot over medium-high heat; bring to a boil. Reduce heat, and simmer 30 minutes. Strain broth through a sieve into a large bowl; discard solids. Return broth to pan; keep warm.
Cook noodles according to package directions, omitting salt and fat.
Heat a grill pan over medium-high heat. Coat pan with cooking spray. Add onion; cook 8 minutes or until charred on each side. Remove from heat; cool slightly. Slice onion thinly; add to broth.
Add turkey and next 5 ingredients (through salt) to pan; bring to a boil. Cook 2 minutes or until thoroughly heated. Place about 1/2 cup noodles in each of 6 bowls. Ladle about 1 1/3 cups broth mixture over each serving. Serve with cilantro, mint, lime wedges, and jalapeño. Serve with hoisin and Sriracha, if desired.