To make the cashew “yogurt,” combine the cashews, lemon juice, and 6 tablespoons filtered water in a blender and blend on high speed until smooth and creamy, about 1 minute; add more water as needed to achieve a yogurt-like consistency. Pour the mixture into a glass container, cover, and let stand at room temperature for 8 to 12 hours, then refrigerate until cold, at least 1 hour or up to 3 days.
Preheat the oven to 350°F. Drizzle a 9- by 13-inch baking dish with 1 tablespoon of the olive oil.
To make the meatballs, in a medium bowl, combine the lamb, parsley, mint, oregano, garlic, red pepper flakes, and chia seeds. Mix well. Form the mixture into 12 evenly sized balls and place them in the prepared baking dish. Bake until firm, 10 to 12 minutes.
To make the salad, in a large bowl, combine the tomatoes, cucumber, and scallions. Drizzle with the vinegar and the remaining 1 tablespoon olive oil, and toss well.
Divide the salad among 4 plates. Place 3 meatballs alongside the salad on each plate, drizzle generously with cashew “yogurt,” sprinkle on some fresh dill, if using, and serve.