Combine olive oil, rice vinegar, lemon juice, mustard, garlic, salt and pepper. Divide in half.
Place quail breasts in half of the marinade for 2 – 3 hours in the refrigerator.
Whisk mayonnaise into other half to make dressing.
Remove breasts from marinade. Heat skillet over medium heat. Brown breasts until just cooked, but not overcooked.
For each plate, place quartered Romaine heart on plate. Top with spring mix. Arrange grilled breasts over lettuce with avocado, grapefruit and onion.
Drizzle dressing over. Top with chopped almonds.