The advice from JONA and Elizabeth are very good. For trees and plants of any kind, my rule of thumb is to feed it just before or with growth spurts. Usually that is in the spring and a boost after the harvest to replenish what was taken from the plants.
For some fruit trees that give more than one crop like my calamondin, Meyer lemon, and some repeat blooming ornamentals, it means fertilizing 2-3 times a year. Avocado, Persian Limes, Bartlett Pears which only fruit once a year get fed in the Spring just before their growth spurt and again after the harvest is done. I use slow N fertilizer and since my growing season is much longer than yours, I also use osmocote, nutricote, or Apex slow release fertilizers ( balanced with micros ) three times a year, if I am good for a regular slow feeding. It does not hurt to add a layer of compost under the trees as well. For shallow rooted trees they cannot be dug in. But forking the ground helps to improve water drainage and compost on top, not only mulches, but the soil organisms and worms below ground will come up and pull the compost down. Remember to fertilize trees around their natural drip line. (This would be where the canopy would be if it were never pruned). Most trees have a root system that mirrors the canopy underground. Most of the roots will be within the top 3 feet of soil where most of the nutrients and water are.
Happy gardening in Hawaii. Gardens are where people grow.