Coarsely chop 1 ½ cucumbers. Finely dice the remaining half and set aside for garnish.
Place the cucumbers, garlic, yogurt, ¼ cup olive oil, dill, basil, Irish Sea Moss, and lemon juice in a blender and blend until smooth. Season to taste with salt and pepper. Chill for at least 4 hours.
To serve, garnish with finely diced cucumbers, dill, and green onions.