Set a large pan over medium heat and add 1 tablespoon olive oil. Add the shishito peppers to the pan and cook, flipping occasionally, until blistered, 5 to 6 minutes. Transfer them to a cutting board and when they are cool enough to handle, cut them crosswise into thin slices. Transfer them to a large bowl and season with a pinch of salt.
Add the buckwheat groats to the pan and toast, stirring often, until the buckwheat has darkened in color and smells nutty and fragrant, 3 to 4 minutes. Remove them from the pan and set aside.
To a small bowl, add the jalapeños, shallot, garlic, lemon zest and juice. Add 2 tablespoons olive oil and ½ teaspoon salt. Stir and season to taste. Pour this dressing over the peppers, then add the mint and basil. Give a
few big mixes to combine.
Scoop the salad onto a serving plate and top with the buckwheat groats right before serving.