6 ounces uncooked wide rice sticks (rice-flour noodles)
1 tablespoon canola oil
1 cup thinly sliced green onions
2/3 pound top sirloin steak, cut into thin strips
2 cups sliced shiitake mushroom caps
2 garlic cloves, finely minced
1 (6-ounce) bag washed baby spinach
2 tablespoons rice vinegar
1 tablespoon fresh lime juice
3 tablespoons lower-sodium soy sauce
2 teaspoons grated peeled fresh ginger
2 teaspoons Sriracha (hot chile sauce)
1 tablespoon dark sesame oil
1/4 teaspoon salt
2 teaspoons sesame seeds, toasted