Preheat oven to 350 degrees Fahrenheit. Line a baking sheet with parchment paper or Silpat.
Make flax "egg": In a small bowl, mix ground flaxseed with water. Let sit 5-10 minutes until it becomes gelatinous.
Add coconut oil, cane sugar, and coconut sugar to a mixing bowl. Using a hand mixer, mix on low-medium until mixture resembles wet sand.
Add vanilla extract and flax egg. Mix with a hand mixer until just combined.
In a separate mixing bowl, whisk together flour, baking soda, and salt.
Add flour mixture to wet mixture and using a hand mixer, mix until just combined. If the dough is too firm, add water 1 tablespoon at a time until desired consistency is reached. The dough should be pliable.
Using a rubber spatula, fold in chocolate chips.
Using a cookie scoop, make cookies and transfer to a baking sheet. Bake for 10-12 minutes. Let cool slightly before transferring to cooling rack. Top with sea salt!