2 Remove excess fat from the chicken legs. In a glass bowl, combine tequila, lime juice, orange juice, chillies, garlic, cilantro, and olive oil, whisking to incorporate. Add chicken and coat completely with marinade. Cover and refrigerate for at least two hours, or overnight, turning chicken several times.
4 Combine garlic, lemon juice, lime zest, tequila, brown sugar, and mustard. Add olive oil while whisking. Season with salt and pepper. Set aside.
6 Preheat oven to 350º F.
7 Heat a grill pan until smoking hot. Remove chicken from the marinade and grill until black grill lines appear, (about 4 to 6 minutes on each side). Remove from pan and set aside.
8 Transfer chicken to a baking pan or dish, dot chicken with butter, and bake for about 30 minutes, or until chicken is golden brown and juices run clear. (Internal temperature should read 165º on an instant read meat thermometer. )
10 Toss the watercress or spring greens, avocado and grapefruit together with the tequila dressing. Arrange chicken and salad on individual plates. Drizzle with dressing and serve with fresh lime.