Preheat the oven to 325° and line a baking sheet with parchment paper. In a medium skillet, combine 1 tablespoon of the sugar with 1 tablespoon of water and cook just until the sugar is dissolved. Add the almonds and toss to coat. Spread the almonds on the prepared sheet and bake for 10 minutes, until tacky and just beginning to brown. Sprinkle with salt, stir and bake for about 10 minutes longer, stirring once or twice, until golden. Let cool completely.
Meanwhile, in a medium saucepan, combine the remaining 2 tablespoons of sugar with the cocoa powder, brown sugar and a pinch of salt. Add the corn syrup and the cream and whisk until smooth. Bring to a boil over high heat for 30 seconds. Remove from the heat and whisk in the chocolate chips and butter until melted. Stir in the vanilla.
Scoop vanilla and chocolate ice cream into banana boats and lay the halved bananas alongside. Top with hot fudge sauce, whipped cream and candied almonds and serve right away.
The fudge sauce and candied almonds can be made 1 week ahead. Rewarm the sauce before serving.