- 1 1/2 cups finely chopped green tomatoes (1/2 lb)
- 1 1/2 cups finely chopped red watermelon
- 2/3 cup minced red onion
- 1 (2 1/2- to 3-inch) fresh red or green chile such as Thai or serrano, minced (including seeds)
- 1/4 cup chopped fresh cilantro
- 1 teaspoon fresh lime juice
- 3/4 teaspoon salt
- 6 (6-oz) center-cut pieces striped bass fillet with skin or mahimahi (1 inch thick)
- 1 1/2 tablespoons olive oil
- Prepare gas or charcoal grill for cooking. If using charcoal, open vents on bottom of grill, then light charcoal. Charcoal fire is medium-hot when you can hold your hand 5 inches above rack for 3 to 4 seconds. If using a gas grill, preheat burners on high, covered, 10 minutes, then reduce heat to moderately high.
- Toss together tomatoes, watermelon, onion, chile, cilantro, lime juice, and salt. (Do not make salsa more than 1 hour ahead or it will become watery.)
- Pat fish dry, then brush with oil and season with salt. Grill fish, starting with skin sides down, on lightly oiled grill rack, turning over once, until just cooked through, 8 to 9 minutes total.
- Serve fish topped with salsa.