For the vinaigrette: Whisk together the tequila, agave, cumin, lime juice and olive oil. Season with salt and pepper.
For the ensalada: Peel and cut the jicama into julienned slices. Open the black beans and lightly rinse under cold running water to remove some of the excess starch. Slice the scallions and finely slice the jalapeno into paper-thin rounds (remove the seeds for less heat). Combine everything together along with the corn and bell peppers in a large bowl and mix well. Dress with the vinaigrette and top with a sprinkle of the cilantro and chili powder.