First, cut and separate your lumpia wrappers. The wrappers should be cut in half diagonally across into triangles. You have to work fast or else the wrappers will stale, so keep the wrappers in a wet kitchen towel if needed. Get a bowl of water ready for rolling and a big tupperware container to keep your rolled lumpias covered.
Combine the vegan ground meat, finely diced onion, soy sauce, salt, and pepper in a large bowl, and mix until well blended. Don't be afraid to get your hands dirty!
Lay down one sheet of lumpia wrapper with the long side closest to you and the tip of the triangle pointing away from you. With your fingers, take about a tablespoon of meat and place it across the bottom of the triangle in a skinny strip, leaving about 1 cm of the wrapper bare on the bottom and about 1 ½ inches bare on both sides. (see photo)
For rolling, first dip your fingers in a bowl of water and pat along the sides of the wrapper to slightly wet it. Fold in the two corners on the sides, then tightly roll the lumpia all the way up to the tip of the triangle. Repeat until all the meat or all the wrappers are gone, keeping the rolled lumpia covered in a tupperware. Freeze the lumpia for at least 30 minutes before frying. They can be kept frozen in the fridge to fry at a later date.
Deep fry in a heavy pan with enough oil to cover the bottom half of the lumpia. Fry until brown and crispy, flip, and repeat on the other side ( ~2 mins per side). Lower the heat as you go so the lumpias don’t burn. Transfer the fried lumpias to a bowl or plate lined with paper towel to drain, then serve immediately.