Grind the garlic and bay leaves together in the work bowl of a hand blender or mini chopper. (Alternatively, chop the garlic by hand and finely crumble the bay leaves and combine.) Add the port, 1 tablespoon of the olive oil, the vinegar, paprika, and salt and pulse until well combined.
Pour the mixture over the chicken, cover, and refrigerate for 1 to 2 hours.
Just before cooking, chop enough cilantro to make 1/2 cup. Scatter the cilantro on a serving plate.
Heat the remaining 1 tablespoon of olive oil on medium-high heat in a wok or large skillet. With a slotted spoon, scoop the chicken pieces out of the marinade and into the hot oil, arranging the chicken in a single layer and discarding the marinade. Cook until browned on the bottom, 2 to 3 minutes, then stir-fry until cooked through, 2 to 3 minutes more. Scoop the chicken out of the pan, leaving any excess oil behind, and place the chicken on the cilantro.
Add the onion to the oil in the hot pan, return it to medium-high heat, and cook, stirring, until the onion is browned at the edges, about 2 minutes. Scoop the onion out of the oil and strew it over the chicken.
Serve the plate of chicken bites hot or at room temperature, sprinkled with a touch of salt and with cocktail picks or toothpicks for handling.