Soak the dates in hot water for about 1 hour.
Preheat oven to 180°C/350°F and oil a rectangular tart form with coconut oil.
For the crust mix ground oats, corn starch, salt and coconut blossom sugar in a bowl. With your fingers rub the cold coconut oil into the flour. Add the water and knead into a smooth dough. Roll into a ball. Refrigerate while you make the filling.
Drain the dates and place in a food processor along with coconut milk and oil, vanilla, cinnamon, ground chia seeds and water. Process until you have a creamy and smooth consistency.
Press the dough into the tart form and poke several times with a fork. Bake on the middle rack for 10 minutes.
Take out the tart form and spread the date cream evenly on top. Distribute the pecan nuts on top and bake for 15 minutes on the middle rack. Take out and leave to cool.