Preheat oven to 350°F. Place cookies and sugar in bowl of food processor. Process 30 seconds, or until finely ground. Add butter, and process until blended. Divide cookie mixture between 24 mini-muffin pan cups (about 1 ¼ packed teaspoons per cup). Using your fingers and/or the back of a rounded teaspoon, press cookie crumbs evenly onto bottoms and ⅔ of the way up sides of cups. (Leave about ¼” headspace.) Bake until firm, 10 minutes. Let cool in pan.
Meanwhile, bring coconut milk, salt and sugar to a boil in large saucepan over medium-high heat. Boil until reduced to 1 cup, about 12 minutes. Remove from heat; whisk in coconut oil. Turn down to medium heat and cook, stirring frequently with a silicone spatula, until caramel-colored and thickened (260° on a candy or instant read thermometer), scraping bottom of pan to prevent scorching.
Remove from heat, and stir in cream and vanilla. Let cool 10 minutes to thicken slightly, then spoon into prepared tart shells. Refrigerate 20 minutes to firm up.
Microwave cream in microwave-safe bowl for 20 seconds or until almost simmering. Add chopped chocolate and let stand 5 minutes. Stir together until blended. Let stand 5-8 minutes, stirring occasionally, until thickened slightly.
For each tartlet, flatten already placed caramel lightly, with finger or back of spoon, to level. Spoon ganache on top of caramel, and spread around with back of spoon to cover. Sprinkle each tartlet with a few grains of sea salt.