Skewer each banana slice with 1 cocktail pick and place on a parchment-lined baking sheet. Freeze for 1 hour.
Pour water to a depth of 1 inch into bottom of a double boiler set over medium heat; bring to a light boil. Reduce heat to medium-low and simmer. Place chocolate and oil in top of double boiler and cook, stirring often, until chocolate melts and mixture is smooth, about 4 minutes.
Dip 1 skewered banana slice in chocolate mixture; immediately sprinkle with a pinch of coconut and return to baking sheet. Repeat procedure with remaining coconut for 5 more banana slices, then with almonds for 6 banana slices, then with sea salt for remaining 6 banana slices. Freeze bites for 1 hour before serving.