Looks to me like a Kohala longan. Suggest very light fertilizing during flowering and medium fertilizing once fruits starts to form, once per month. Then heavy fertilizing (and pruning) after fruit set is all finished. Go easy on N, and heavyon P and K during flowering and fruiting, then when finished fruiting go heavy on N.
Watering during fruit set should be deep and consistent. If you thin the fruits you will certainly get very large fruits. Kohala tends to have large size fruits anyway.
On a tangent, i've noticed that longan fruits can keep surprisingly well in fridge for very many months. It's rather amazing, i just had the fruits in the fridge to keep the seeds fresh. But opening them up 3-4 months later most of the fruits were all still fine and delicious. Can't do that with lychees, rambutans or pulasans!