In a pot, mix the chicken, vinegar, soy sauce, garlic, bay leaves, sugar and peppercorns. Refrigerate for at least 1 hour.
Transfer the pot to the stove; add enough water to cover the chicken. Bring to a boil; lower the heat and simmer for 40 minutes. Transfer the chicken to a plate. Boil the sauce until reduced to 4 cups, 15 minutes. Strain through a sieve; skim the fat.
Shred the chicken, discarding the skin and bones. In a food processor, pulse the chicken until finely chopped. Mix in the chives and 1 1/2 cups of the sauce (reserve the remainder for another use).
Lay out 1 wrapper on a clean surface. Spread with 2 heaping tbsp. of filling in a thin line along one edge. Brush the opposite edge with the egg wash, fold in the edges and roll up tightly. Repeat.
In a medium pot, heat 2 inches oil to 375 degrees . Working in batches, fry the rolls until golden, 2 minutes. Transfer to paper towels to drain; sprinkle with coarse salt.
Cut each lumpia into 3 pieces. Serve with the desired toppings.