1. Preheat a grill or broiler to high heat.
2. Peel garlic. Slice jalapeño in thirds, cutting away white veins and removing seeds. Place both in the bowl of a food processor or blender.
3. Season steak on both sides with 1?2 tsp. of the pepper. If using a grill, place steak directly on grill. If using a broiler, place steak on a rimmed baking sheet lined with foil sprayed with vegetable cooking spray. Cook on each side for 5 to 8 minutes, depending on desired doneness (5 to 6 minutes formedium-rare, 7 to 8 minutes for medium).
4. While steak cooks, prepare pesto. Add arugula and pistachios to the foodprocessor with garlic and jalapeño. Pulse a few times until coarsely minced. Add cheese and salt to mixture and pulse again until combined. Scrape down the sides of the bowl. Through the feed tube, add 2 Tbsp. lime juice and 3 Tbsp. oil to the mixture while pulsing, until fully combined and smooth. The pesto will be thick.
5. Slice tomatoes in half and thinly slice each half into half-moon slices. Cut avocado in quarters, and slice each wedge into thinner slices. Divide tomatoes and avocados among 4 dinner plates. Drizzle each with a bit of the remaining 1 Tbsp. lime juice and sprinkle with remaining 1?2 tsp. pepper.
6. When steak is done, let rest for 5 minutes before slicing. Slice steak across the grain and divide among the 4 plates. Top with arugula pesto and serve immediately.
Source: Fresh Magazine March, April 2010