For the spicy tequila: Pour the tequila into a small jar and add the jalapeno. Cover and let sit overnight or up to 2 days if you want it really spicy. Strain, discarding the jalapeno. Cover and store in a cool, dark place.
For the spicy tequila sunrise: Fill a tall glass with ice. Pour in the orange juice and spicy tequila. Slowly pour in the grenadine and watch it sink to the bottom; do not stir. Garnish with the orange and jalapeno slices and a cherry.