Line a small baking sheet or plate with parchment. Core the apple and slice crosswise into about 1/4-inch rounds; you should get 3–5 usable rounds depending on apple size. Pat the slices dry with a paper towel to remove excess moisture and set on the parchment.
Toast the shredded coconut in a dry skillet over medium heat, stirring constantly, until fragrant and just turning golden (1–2 minutes). Transfer to a small bowl and let cool 2 minutes so it isn’t steaming when mixed with the nut butter.
In a separate bowl stir together the almond butter, maple syrup, and cinnamon until smooth. Fold in the toasted coconut until well combined; the mixture should be spreadable but not runny. If it feels too loose, chill the bowl in the fridge for 5–8 minutes to firm slightly.
Use a teaspoon or a small cookie scoop to mound the coconut-almond mixture onto each apple round, gently pressing so it adheres and forms a slight dome.
Place the apple rounds back on the parchment and put them in the freezer while you melt the chocolate. Place the chocolate chips and coconut oil in a small heatproof bowl and melt over a double boiler or in 20-second bursts in the microwave, stirring between bursts, until smooth.
Remove the apples from the freezer and quickly drizzle the melted chocolate over each topped slice using a spoon. Return to the freezer or refrigerator until the chocolate firms, about 5–15 minutes. Serve chilled or at cool room temperature. Sprinkle with a pinch of flaky sea salt if desired.