In a large mixing bowl, combine 2 tablespoons of the sambal, the soy sauce, ginger, chicken, water chestnuts, garlic, scallions, cilantro and 2 tablespoons water (this will keep the meatballs really moist!). Use your hands to squish the mixture together until combined.
Form a little tester patty and then cook and taste to make sure the chicken is really delicious. If the seasoning isn't just right, add a little more soy sauce or a sprinky-dink of salt. When you're confident the meatball mix is perfectly seasoned, form the meatballs.
Roll the meatballs in the peanuts, and place on a small baking sheet. Roast until meatballs are cooked through, 12 minutes.
In a small bowl, add the mayonnaise and the remaining 2 tablespoons sambal. Stir to combine and refrigerate until ready to serve.
Serve the meatballs hot with the chili-mayonnaise.
Also Pictured: Hoisin-Glazed Bacon Bao Buns with Sauteed Mushrooms and Pickled Vegetables Pork and Shrimp Gyoza Red Curry-Lime Chicken Wings