Place the cucumbers in a colander and toss with salt. Let them drain, stirring every 10 minutes or so, for at least half an hour. For optimal results you can even do this in the fridge overnight.
Rinse the salt off of the cucumbers and dry them by thoroughly patting them down, or spinning them in your salad spinner.
For the vegan cashew-pine nut "mayonnaise":
Combine all ingredients in a blender or food processor, stopping to scrape down the sides as needed. Add only enough water to blend everything smoothly. If you have a high-speed blender you may not need any. Adjust seasoning and sweetness to taste.
To assemble the vegan cucumber salad:
Soak the chopped raw red onions in a small bowl of tap water for 5 to 10 minutes, and then drain. (This is to temper the aggressive raw red onion flavor a little bit.)
Combine the cucumber, chickpeas, red onion, and dill in a bowl. Fold in the cashew-pine nut "mayonnaise". Taste for seasoning and add salt/pepper/additional dill as needed.
Serve cold.
Notes
To substitute for the brown rice syrup, use agave nectar or sugar. Start with 1 tsp since brown rice syrup is not as sweet, and adjust to taste.