To make rice and satay, heat oil over medium flame in a small saucepan. Add onion; sauté until softened, about 1 minute. Stir in rice. Pour in chicken broth, and bring to a boil. Reduce heat; cover and simmer until rice is tender and all liquid is absorbed, about 45 minutes.
Meanwhile, lay salmon fillet on a cutting surface with a short end facing you. Cut fillet in half from top to bottom. Make 6 equal cuts across fillet, creating 12 pieces. Insert an 8-inch bamboo (or other wooden) skewer through the short ends of each piece. Arrange salmon in a single layer on a rimmed baking sheet. Brush both sides evenly with pesto. Cover with plastic wrap and refrigerate 30 minutes.
Remove rice from heat; let stand 10 minutes. Spray a nonstick griddle or large skillet with cooking spray; heat over medium-high flame. Lightly coat salmon with cooking spray. Cook until browned on each side and just cooked through, carefully turning with spatula, 1 1/2 to 2 minutes per side.
To serve, spray four 4-ounce ramekins with cooking spray. Divide rice into ramekins, pressing lightly with spoon. Invert ramekins onto warm plates to loosen rice and sprinkle with sesame seeds. Lay salmon skewers over rice; garnish with herb sprigs.