Stir white chocolate, oil, matcha and salt in a medium heatproof bowl set over a saucepan of simmering water for 2-5 minutes until nearly smooth. Remove from heat; stir until chocolate is melted. Set into a larger bowl of ice water and chill, stirring constantly, until thickened and just starting to lose its sheen – about 2 minutes.
Working one at a time, dip berries into matcha-chocolate mixture to coat. Let excess drip back into the bowl. Place on a parchment-lined baking sheet or cooling rack and sprinkle with sesame seeds. Chill dipped berries until shell is set, 20-25 minutes.