Combine the soda, soya sauce, vinegar, minced onion, garlic, ginger and coconut crystals in a bowl. Add chicken and turn to coat. Place in refrigerator over night.
Remove chicken from marinade and pat dry. Reserve 1 cup of marinade.
Heat one teaspoon of coconut oil in a large skillet. Add the chicken and heat on medium high, turning once for 8-10 minutes, until browned and transfer to a plate.
Wipe out the skillet. Heat remaining 1 teaspoon of coconut oil. Add the sliced onion and asparagus. Cook for 5 minutes until browned. Add the reserved marinate and boil until slightly reduced. Add the cilantro.