Line an 8 by 8 inch baking pan with parchment paper.Place zucchini and water in a pan and bring to simmer. Steam with lid on for about 5 minutes.Drain and discard water.Transfer zucchini to a blender and add coconut oil and lemon juice. Blend on highest speed until completely smooth.Add gelatin, optional nutritional yeast, and salt. Blend again until smooth.Poor mixture into prepared pan and spread in an even layer.Refrigerate for 2 hours, or until set.Remove and cut into desired sizes.