Broil the tomatoes - Halve the cherry tomatoes, cutting through the stem end from top to bottom. Arrange on a baking sheet, cut side down, and broil for about 3 minutes, until slightly charred.
Combine the other ingredients - In a medium bowl, add the mustard, honey oregano, miso paste, and black pepper. Stir to combine.
Toss - Toss the broiled tomatoes with the mustard mixture, until evenly distributed.