While cucumber and tomatoes are marinating, make the dressing by combining rice vinegar, soy sauce, sugar, garlic, sesame oil, chili oil, and pinch of salt together. Set aside.
3 Tbsp rice vinegar, 2 Tbsp soy sauce, 1 Tbsp granulated sugar, 3 cloves garlic, 2 tsp sesame oil, 1 Tbsp chili oil, Pinch of salt