1. In a large bowl, mix cilantro, scallions, garlic, ginger, soy sauce and mustard. Add tuna and stir to coat.
2. Make 16 patties out of tuna mixture. Place patties on a plate and refrigerate for 30 minutes.
3. Heat 1 tsp. olive oil in a nonstick skillet over medium-high heat. Add 5 or 6 patties and cook until just cooked through, 2 to 3 minutes per side. Repeat with remaining patties.
4. Top each bottom bun with lettuce, if desired, 1 slider and 1 tsp. pickled ginger, then cover with top bun. Serve immediately.